The arrival of high-speed rail (see ITRANSPORTE 69) requires the adaptation of the passenger buildings in the four main stations of the Autonomous Community of Extremadura: Plasencia, Cáceres, Mérida and Badajoz, to the needs of the new railway service. Ineco, in addition to directing the work on the four stations and working on the track renovation, has drafted the remodelling projects for Adif Alta Velocidad, the Spanish railway infrastructure administrator, which include the buildings, entrances and the surrounding area, as well as the platforms, shelters and underpasses.

All of the works follow general guidelines with the common objectives of improving the sustainability and accessibility of the facilities. Outside, the main works consist of the creation of plazas in front of each station, in which the pedestrian is given centre stage. On the façades, the installation or renovation of shelters will highlight the entrance doors. The aim is to improve the integration of the stations into the urban fabric.

In the interior, the general concept is to gain more natural light, for which suspended ceilings are eliminated, increasing the height in the halls and opening up the spaces. The use of sustainable materials, improved air-conditioning efficiency and the installation of LED lighting are all part of the project. Furthermore, all of the spaces are totally accessible, and include technologies such as Wi-Fi, electric vehicle charging areas and personalised information points.

In order to carry out these works, it has been necessary to make the service compatible with the works, which is why personnel have been moved to provisional modules so that they can continue to provide service, and the works have been carefully designed to guarantee passenger comfort at all times.

Badajoz station

A new urban space

It was opened in 1866 and initially had a façade topped by a pediment with a skylight, decorative elements widely used at the time. These were later replaced by a rectangular screen façade with 24 openings and a shelter. The housing for railway personnel that began to be built around the station became what is today the neighbourhood of San Fernando. The station has two platforms.

The works reorganise the exterior space, where pedestrian traffic predominates, while inside the passenger building the spaces are being completely remodelled. A large plaza will be created in front of the building as a space for relaxation and enjoyment, integrating it into the neighbourhood, respecting the symmetrical composition and enhancing the building as a scenic backdrop for Avenida Carolina Coronado. On the main façade, the openings in the lower band are strengthened by metal frames in the form of lanterns and there is a lattice of metal slats above. These match existing slats in the central body of the entrance and their orientation changes, giving movement to the arrangement.

A new shelter will be installed outside to cover the entrance. The interior remodelling is centred on the central body, which houses the hall and main entrances, and the eastern body, which contains various auxiliary facilities. A double height hall is created with an open and naturally lit waiting area, enhancing the central character of the space. The underpass and platforms are also being remodelled.

Cáceres station

A renovation that respects the ‘skin’ of the building

The existing station dates from 1963 and replaced the original one, inaugurated by King Alfonso XII in 1881, which was demolished. The new building was designed longitudinally, with a symmetrical façade formed by a central body and two lateral bodies with towers at both ends. The main entrance is protected by a large semi-circular shelter. Inside, the waiting room is decorated with a ceramic mural by the artist José Luis Sánchez, dedicated to the conquest of America, and the platform façade has a stained glass window with railway motifs (tracks, turnouts and signals).

The station has two platforms with three operational tracks for passengers and an underpass equipped with lifts.

The work includes urban operations to ‘create the city’ and works on the passenger building that highlight the value of this architectural piece. The conversion of the public space in front of the passenger building into a large square connects the station to the rest of the urban fabric. The arrangement opens the passenger building up to the city, making it part of the architectural scene of Cáceres. Pedestrians, cyclists and public transport (taxis and buses) will converge in this new urban space.

The integration of the passenger building is achieved renovating the building’s ‘skin’, while respecting its dimensions and construction. It is made up of a lightweight set of horizontal aluminium slats, which will shape the structural bays of the building, giving movement to the façade and breaking up the flatness of the existing building. A new car parking area will be created, which will be detached from the façade of the passenger building, giving the complex space and clean lines.

In the interior spaces intended for travellers (hall, toilets and underpass), the finishes will be renovated and the sunlight and ventilation conditions will be improved. All this is accompanied by new facilities that improve the energy efficiency and comfort of the station.

In the platform area, the shelter will be renovated with new waterproofing, and the underpass between platforms will be resurfaced and given new flooring, as well as new glass railings combined with stainless steel.

Plasencia station

Opening up spaces while preserving the building’s identity

The station was opened in 1893, as part of the ‘Ruta de la Plata’ line to Astorga, which is now closed. The passenger building, in a simple and sober style, has a central body of two floors with three linteled openings each, and two side annexes. The roof is a gabled tile roof with the original support structure from 1893, which has been preserved with energy improvements in the insulation. It is located outside the town centre, south of the Jerte River. It has two platforms (one is a service platform), with three tracks and several more that are no longer in use, a freight dock (which will house the cafeteria space) and a building formerly used for railway residences.

The project is mainly focused on development, entrances and buildings. A new station square will be created, with road access and parking adjacent to the station buildings, separate from the development area and façades of the buildings. The cargo building attached to the station, which will house the future cafeteria, will be refurbished, creating a transition space between it and the passenger building, which will be marked with a new shelter, as well as the taxi stand and the main entrance to the station.

In the passenger building, all of the interior spaces are being renovated by extending the hall to the current cafeteria area (which is being moved to the renovated building); new restrooms are being built, and a double height main space is being created by demolishing the first floor, which gives a greater sense of space and light. The works include structural reinforcement, remodelling of the installations and improvement of the building roofs, conserving the support structures of the roofs (riveted wood and steel), to preserve the buildings’ original character. During the construction phase, materials that have added value due to their special historical characteristics, will be reused, such as part of the original tiles, which will be restored and reused for the roofs. In the interior, the furniture and lamps are being updated with more modern designs.

Mérida station

Restoring harmony

This is the largest station in the Extremadura network in terms of size and passenger traffic, and several lines converge here. It was opened in 1864 and is very close to the historic centre of the city. As with the previous buildings, the passenger building is arranged with a central body with two floors plus side buildings. It has more than 10 tracks and a cargo area.

In the solution designed for the Mérida station, special attention has been given to harmonising the spaces that make up the complex in order to recover the spatial quality that has been lost over time. In terms of development, a new well-defined access plaza space will be created while respecting the retaining wall structures. This will create a homogeneous space in which the pedestrian area is differentiated from the roadway, creating transition spaces that frame the large backdrop of the passenger building’s façade. This same idea was adopted inside, with the hall as an articulating element and a new corporate style. This hall has been designed as a dominant space, incorporating passenger services and the commercial area. The edges of the existing platforms will be adapted to allow passenger access to the new trains. The underpass will also be completely renovated.

The stations of Extremadura, yesterday and today

The four original stations were opened between 1864 and 1893, and from an architectural point of view they have the characteristics of the period: simple lines and a functional design typical of 19th century industrial buildings. The regulations at that time established general guidelines for the different existing railway companies to maintain a certain aesthetic continuity in their facilities. It was recommended that stations located in rural areas be simple constructions that fit in with the surroundings, with decorative elements reserved for urban stations. All of them share a common feature: the passenger building as the main construction, plus other annexed facilities, which include locomotive and wagon depots, workshops, warehouses, docks, scales or watering (water supply to steam locomotives), such as the one at Cáceres station. There used to be a house for the Station Manager and sometimes also for the railway staff, as in Mérida and Plasencia, and in some cases these gave rise to entire neighbourhoods, such as San Fernando in Badajoz.

As for the passenger buildings, these are symmetrical constructions, with one or two floors, with the main façade in a central body that is higher and more prominent than the rest, with annexes on both sides, and gabled roofs, as in the case of the Merida station. The walls were usually made of stone, painted white or light colours, and the door and window openings, corners and ledges were framed in ochre, brown or blue-grey.

Works in Plasencia. The works include the restoration and reuse of some original materials, such as wood, rivets and part of the roof tiles. In the picture, the station’s shaded walkway.

The arrival of high-speed rail in this region in northwestern Spain had its first historical milestone at the end of 2011, with the entry into operation of the 150-kilometre stretch between Ourense, Santiago and A Coruña. After the service commissioning of the line between Olmedo and Zamora in 2015, all that remained to complete the connection between Galicia and the centre of the Iberian Peninsula was the construction of three sections totalling approximately 230 kilometres: Zamora-Pedralba de la Pradería, Pedralba de la Pradería-Taboadela and Taboadela-Ourense.

The difficult route between Pedralba and Ourense

Built for the most part on two separate tracks, the 101-kilometre section between Pedralba and Ourense crosses the different mountain ranges that form the Central Ourensan Massif, a route that the AVE will be able to cover thanks to the construction of 32 viaducts and 31 tunnels, many of them bi-tube, or with one tube for each track. More than 60% of the route was either underground or over viaducts and required special works: in total, the section has almost 11 kilometres of viaducts, the longest of which is the Requejo viaduct (1.72 km), and 126 kilometres of tunnel (62.45 km on the right-hand track plus 55.87 km on the left-hand track and 7.84 km of double track), the longest being the O Corno tunnel (8.6 km).

MADRID-GALICIA HIGH-SPEED LINE. The Madrid-Galicia HSL is co-financed by the European Regional Development Fund (ERDF), ERDF/Cohesion Fund 2007-2013 and Spanish Multiregional OP 2014-2020.

The works that are covered in this report belong to this complex route between Pedralba and Ourense, which Adif Alta Velocidad constructed to provide the highest levels of railway technology, with standard-gauge double track (1,435 mm) throughout the route, and designed for speed limits of up to 350 km/h, with 2×25 kV 50 Hz alternating-current electrification, ERTMS Level 2 and Asfa traffic control systems, and a GSM-R mobile communications system.

Five of the most notable works

THIS SECTION FEATURES A NUMBER OF INFRASTRUCTURES THAT STAND OUT FOR THEIR COMPLEXITY, EITHER IN TERMS OF THE CONSTRUCTION METHODS USED, THEIR DIMENSIONS OR THEIR ENVIRONMENTAL CHARACTERISTICS.

1. The jacked caissons of the Requejo tunnel

Two caissons 80 and 100 metres long jacked under the conventional railway tracks complete the Requejo tunnels.

In the foreground, shoring of the track. Behind, crossways, one of the two caissons already executed. In the background, the opening of the Requejo tunnel.

Several kilometres from Pedralba, the AVE works are progressing through the mountains of the Sanabria region with several notable actions, including the construction of the caissons jacked into the Requejo tunnel, structures built in situ at the western opening of the Galicia side and jacked under the railway tracks, allowing Adif to maintain rail service on the Zamora-A Coruña national gauge line, which intersects with the new high-speed line at this point.

This intersection of the high-speed line with the conventional track was resolved by constructing two reinforced concrete caissons measuring 8.5 metres high and 8.5 metres wide on the inside, with lengths of 79.5 metres for the caisson for the right-hand track and 100.5 metres for the caisson on the left.

In their final position, the caissons form the cut and cover exits of the Requejo tunnels. The execution procedure included the shoring of the conventional track and the construction of engineering structures on a sliding platform close to their final location prior to subsequent relocation by means of a hydraulic jacking across the track to their final positions.

The shoring consisted of a metal structure that allowed the caisson to be moved without affecting the track, ensuring its stability. Due to the shoring work, trains had to run at a speed limit of 30 km/h during the works, as opposed to the normal speed of the route in this area of over 100 km/h. The speed restriction was necessary as a safety measure because the level and alignment of the track in this situation can generate movements that are not compatible with higher speeds. Given the jacking lengths, the caissons were divided longitudinally into two sections that were jacked successively, each with a corresponding battery of 15 hydraulic cylinders with a force of 300 tons per cylinder. At the same time that the successive 50- centimetre thrusts were carried out, the earth was removed by mechanical means, ensuring that the stability of the tracks was not compromised, until the structures reached their final positions.

2. The Padornelo tunnels

A high-speed tunnel built just 20 metres from the longest tunnel on the entire Spanish conventional line.

Ineco provided construction management for Adif Alta Velocidad on this 6,406-metre tunnel with a 52-square metre clear cross-section, which runs parallel to the tunnel of the Zamora-A Coruña national gauge line, and is located between the municipalities of Requejo and Lubián (Zamora), below the Padornelo mountain pass.

The Padornelo tunnel is part of the Padornelo-Lubián section, and consists of the supporting layer of the single UIC-gauge track on the right, measuring 7.6 kilometres long. The left-hand high-speed track will be executed at a later stage as part of a new project that will adapt the old 5.97-kilometre Padornelo tunnel on the Zamora-A Coruña line for mixed traffic on the left-hand high-speed track and freight on the conventional line.

Construction was carried out with conventional excavation, applying supports consisting of shotcrete, bolts and trusses. Excavation was carried out by blasting the areas with the hardest terrain and using mechanical means (backhoes, hydraulic demolition hammers, etc.) in the softer ground and terrain with lower geotechnical quality.

Execution was determined by the proximity of the tunnel on the Zamora-A Coruña conventional line. During the works, trains continued to run, so certain protocols were established to monitor for deformations in both tunnels, and reinforcements consisting of mesh and shotcrete were necessary in some sections of the old tunnel. 15 connection galleries were also built between the tunnels and an evacuation platform along the existing tunnel, to create the evacuation route necessary for the commissioning of the high-speed line. To carry out these works, the entire track was renovated with UIC 60 E1 rail, PR-01 concrete sleepers and type 1 ballast.

The works were accompanied by a series of specific environmental and landscape integration actions due to the proximity of two protected areas or sites of community importance (SCI):  the banks of the Tera and Tuela rivers and their tributaries. In this regard, different measures were agreed with the regional authorities to prevent the impact on the protected flora and fauna. One example was the treatment of water coming from the tunnel, which was subjected to different processes before being discharged into the waterway, in order to ensure that its physical and chemical parameters complied with legislation. In addition, from the beginning of the works, the waters of the rivers belonging to the aforementioned SCIs had their physical and chemical characteristics monitored and a follow-up assessment was carried on the area’s populations of Pyrenean desman (Galemys pyrenaicus), brown trout (Salmo trutta), freshwater pearl mussel (Margaritifera margaritifera) and aquatic macroinvertebrates.

3. The Espiño tunnels

Two large high-speed tunnels constructed using eight simultaneous excavation fronts.

View of the western tunnel opening. The tunnels were designed to integrate with the hillside as much as possible.

The Espiño tunnels are unique in that they were excavated simultaneously from four fronts: in addition to the two end fronts, there were also two intermediate excavation fronts. To do this, an intermediate gallery was built that ended in a large cavern, from which four additional fronts could be started for excavation in the direction of Madrid and Ourense. The large number of fronts reduced the excavation times for the tunnel.

The bi-tube tunnel runs through the municipalities of A Gudiña and Vilariño de Conso in the province of Ourense. With approximately 8 kilometres on each track and connections between tunnels every 400 metres (20 emergency galleries), it is one of the largest tunnels in the section.

Both tunnels were excavated using the New Austrian tunnelling method, with top-heading and bench, from the eastern tunnel opening, from the western tunnel opening and from the intermediate galleries of attack towards both tunnel openings. The right-hand track has an exact length of 7,924 metres including 30 and 40-metre artificial tunnels in each of the openings for improved visual integration into the hillsides. The remainder (7,854 m) was mine excavated, that is, under natural terrain. The left-hand track has an excavated length of 7,838 m underground, to which 30 and 36 metres respectively were added to each of the openings as artificial or cut-and-cover tunnels, giving the left-hand Espiño tunnel a total length of 7,904 m. Cut-and-cover tunnel structures were also included for improved visual integration into the hillsides.

The presence of metal sulphides and carbonaceous matter in some slatey rock required the use of technosols to treat some of the excavated material in the waste sites. This technique made it possible to control the oxidation of these sulphides, which are capable of generating acidic water, thus creating a reducing environment and also decreasing oxidation kinetics. Technosols also act as a buffer, adsorbing any heavy metals that may be present in the runoff water in the form of leachate, and are eutrophising, which promotes eventual environmental integration.

4. The Bolaños tunnels

The only two tunnels on the Madrid-Galicia line executed BY TBM.

Assembly of the 230-metre-long, 2,900-ton TBM in May 2015.

The Bolaños tunnels are the only ones on the entire line executed by a TBM. Bi-tube by design, they form part of the Vilariño-Campobecerros section, and consist of a 6.96-kilometre right-hand track and 7.91-kilometre left-hand track. The route runs through the municipalities of Vilariño de Conso, A Gudiña and Castrelo do Val, in the province of Ourense.

Both were executed using a TBM with the exception of the first 55.91 metres of the western opening and the first 15 metres of the eastern opening on the right-hand track and the first 76.13 metres of the western opening on the left-hand track, which were executed by conventional methods to move beyond a fault.

The dimensioning of the tunnel cross-section was limited by compliance with the UIC’s health and comfort criteria to ensure high-quality high-speed passenger transport. Following these criteria, the final open cross-section of the tunnels was 52 square metres. The excavation cross-section of the TBM was 9.80 metres in diameter, with 37-centimetre-thick segments of precast reinforced concrete lining with an internal diameter of 8.76 m. The concrete in the segments contains polypropylene fibres as a fire protection measure. The gap between the TBM excavation and segment lining was filled with two-component mortar, a mixture of conventional mortar with hydrated bentonite and silicate.

The waterproofing of the precast lining was achieved by fabricating the segments with a low-permeability concrete; installing a double waterproofing seal at the segment joints; and injecting the two-component mortar into the space that remained between the excavated surface and the ring of segments. The injected voussoir is the primary waterproofing, since, in practice, it is the first barrier encountered by groundwater on its way towards the interior of the tunnel, with secondary waterproofing being that provided by the seals.

The two tubes are connected by 18 galleries, one of which is used specifically for installations. The cross-section of the galleries has an open width of 4.70 m and a lining of 25 cm of plain concrete, with the addition of polypropylene fibres as a fire protection measure.

During the tunnel excavation, a large amount of water was generated by the construction processes, and it was necessary to treat it in a large treatment plant in order to comply with the parameters required by the competent bodies. The suspended solids present in the water were removed using a separation process, with the help of coagulants and flocculants. The pH was adjusted through the use of CO₂ (for basic process water) or caustic soda (for acidic process water).

5. The Teixeiras viaduct

A 100-metre-high central arch over the Arroyo Teixeiras.

The central piers are over 90 metres high, with two half-arches that provide a separation of 132 metres between them.

The Teixeiras viaduct, for which Ineco was in charge of works and environmental management, is without a doubt the most spectacular structure on the entire Madrid-Galicia HSL.

The deck of the Teixeiras viaduct was executed using self-launching formwork, and has a length of 508 metres distributed in eight spans (56 m + 4×66 m+56 m). Its uniqueness lies in the construction procedure chosen to negotiate the Arroyo Teixeiras with maximum respect for the environment. The foundations of the central piers (which are more than 90 metres high) are shared by two half arches, which were erected and angled inward to meet at a fixed point under the deck, providing a separation between piers of 132 metres, equivalent to two spans, which, in addition to minimising the impact on the environment, gives the structure greater transparency and beauty. The Arroyo Teixeiras, a tributary of the Támega River, has protected riverbank vegetation and, on the surrounding slopes, a forest consisting of native species with large chestnut and oak trees.

The construction of a large structure like the Teixeiras viaduct requires large auxiliary areas to house the facilities that support the construction: from large cranes to site huts; from storage yards to vehicle car parks. For this site, ways of minimising the impact of this area were studied thoroughly. Detailed analysis was carried out on the opening of roads with steep slopes to reduce their grade, areas of auxiliary facilities on bends or between foundations, work platforms adjacent to jobs with strict occupation limits, etc. All of these installations were located on both hillsides that, in addition to being very steep, had soils made up of highly fragmented materials with high potential for displacement of soil that would reach the waterway below in the case of rain.

In order to prevent or mitigate the effects that this soil displacement could have on the water quality of the Arroyo Teixeiras, an ingenious anti-displacement system was implemented, basically consisting of a network of pipes (concrete ditches, pipes, sandpits, settling pools, intermediate reservoirs, etc.) deployed along the access roads to the foundations, which converge at pumping reservoirs located very close to the waterway. To reduce earthwork and facilitate subsequent integration, metal containers were used as pumping reservoirs so that they could be easily removed after the completion of the works.

In the event of heavy rain, sediment-laden runoff was redirected –by means of powerful pumps– to a treatment system located at the height of abutment 2 of the structure, expanding the response capacity in the case of a heavy rains. In this treatment system, coagulants and flocculants were also be used to accelerate separation if necessary.

By the Ineco construction managers Arturo Pastor, Iago Rodríguez-Lorasque and Noelia Cobo, technical engineer Jesús Pena, and environmental worksite managers Iñaki G. Seoane, Enrique M. Agüera and Luis Álvarez-Pardiñas with the collaboration of Raúl Correas, deputy director of Construction V at Adif Alta Velocidad.

Load tests: ready for action

Prior being put into operation, Ineco carried out the load testing of 25 structures and inspection of 70 bridges for Adif on the Olmedo-Pedralba section of the Madrid-Galicia high-speed line.

By Pablo Sánchez Gareta, civil engineer

The Ineco team, from left to right: Jorge Benito, Amadeo Cano, Pablo Martín-Romo, Javier Ortiz, Pablo S. Gareta and Carlos Sánchez.

During the months of March and April 2019, a team of seven specialists from Ineco carried out an important task for Adif Alta Velocidad prior to the commissioning of the new Olmedo-Pedralba de la Pradería section: load testing and inspection of the bridges and viaducts over which the complex route of the Madrid-Galicia HSL runs, all with satisfactory results.

Load tests were carried out on a total of 25 structures, in addition to the main inspections of 70 bridges (14 viaducts, 2 pergolas and 54 underpasses). In the case of the bridges, and since they were newly constructed, the data collected during the inspections provides a baseline situation (zero state) for subsequent analysis and monitoring of the evolution of the structure.

During the tests, which are compulsory for all new bridges with spans 10 metres or longer, actions of actual use of the works are reproduced under controlled conditions.

In other words, checks are carried out to ensure that the bridge is safe, well built and able to withstand the loads of the trains that will travel over it over time. For these verifications, static and dynamic tests are carried out with loaded trains running at different speeds. Data collected by sensors installed on the structure is analysed and the actual and expected responses are compared. The results are sent to the Railway Safety Agency, which is responsible for authorising the entry into operation of the section.

One of the most representative structures that was tested was the Ricobayo viaduct over the reservoir of the same name, measuring 368 metres long and consisting of four spans of between 50 and 155 metres long. For the test, 2 locomotives and 20 hopper wagons loaded with ballast weighing a total of 1,863 tons were used. On the spectacular viaduct over the Tera River, measuring 645 metres long and consisting of nine spans of between 60 and 75 metres, two trains with eight hopper wagons each, weighing a total of 1,536 tons, travelled at speeds of between 10 and 80 km/h.

Gauge matters

While the Zamora-Ourense high-speed section was being completed, a gauge changer was built in Pedralba de la Pradería to enable trains to travel on tracks with two different gauges without stopping. Ineco managed the works, as it is doing in the Taboadela changer at the other end of the section.

By Marta González, and Noelia Sánchez, civil engineers

Ineco is managing works for Adif Alta Velocidad on the Pedralba de la Pradería gauge changer in Zamora, a railway facility that allow uninterrupted travel by trains between Madrid and Galicia, automatically switching from high-speed track in standard gauge (1,435 mm) to conventional track in Iberian gauge (1,668 mm). In addition, at the opposite end of the section, works have also begun on another changer in Taboadela, Ourense, also managed by Ineco.

A gauge changer is a railway facility that allows trains equipped with variable-gauge axles or semi-axles to automatically change their gauge while travelling at a constant speed (approximately 15 km/h) and without the need for human intervention. In Spain, where the high-speed network in standard gauge coexists with the conventional Iberian gauge (IT57), these systems are essential to enable trains to switch from one to another at points where both exist. This is the case of the Pedralba-Taboadela-Ourense section.

From left to right, engineers Noelia Sánchez, head of the ACO unit, and Marta González, manager of the gauge-changer works in Pedralba, Zamora.

The Pedralba gauge changer is a TCRS3 dual gauge changer, that is to say, suitable for both CAF and Talgo technology. Works included the installation of points that connect the Zamora-A Coruña conventional line to the changer at kilometre 112/405. The installations consist of a metal structure with a main trench where the gauge-change platform is located, equipped with a video recording system. On both sides, there are two observation trenches that allow inspection of the rolling system, which also has an automatic de-icing system for Talgo train wheels. This is a temporary solution until the next high-speed section is put into service, at which point the platform and equipment will be dismantled and moved to another changer.

BRIEF HISTORY OF A GROUND-BREAKING TECHNOLOGY

• The first gauge changers were installed in Spain in 1968 in Irún and Portbou to allow Talgo trains to travel to Paris and Zurich.
• Gauge changers spread at the same time as the high speed network; the first generation included different types for each of the two variable rail technologies in Spain (RD by Talgo and Brava by CAF). The dual system, which was suitable for both, was developed later. Adif installed the first third-generation system (TCRS3) in 2009.
• For more than twenty years, Ineco has participated in the design of most of the different generations of gauge changers. Currently, it is also responsible for the maintenance and operation of more than twenty automatic gauge changers throughout Spain.

Pre-validation tests on the line between Antequera and Granada ended on 20 December 2018, when traffic control was transferred to Adif Alta Velocidad. The infrastructure manager then gave the green light for the start of a period of internal ERTMS traffic testing between Antequera and Granada, prior to reliability and training processes. Once this phase is complete, the high-speed AVE connection between the capital of Spain and the city that is home to the Alhambra will be a reality.

The 114 kilometres of line between Antequera and Granada and its direct connection to Málaga via the Gobantes Junction have been built predominantly in standard gauge, 33% double-track and the rest single track electrified at 25 kV with a top speed of 300 km/h. The exception is 26.3 kilometres of mixed-gauge line consisting of three rails where the line passes through Loja and at the entry into Granada. With the commissioning of the new line, Granada is now finally connected to the rest of the Spanish high-speed network through the Córdoba-Málaga line.

Ineco has participated in the development and construction of this line since its beginnings, carrying out various projects that include consulting and technical assistance for the environmental management of the entire final stretch in Andalusia; platform construction management, project and construction management of the Antequera, Loja and Granada high-speed stations; clearance studies and adaptation of the Loja tunnels; consulting and technical assistance for the construction management of track assembly, and power, signalling and communications facilities along the entire line.

Comprehensive rail traffic management

Traffic testing was the final job carried out by Ineco for Adif and Adif Alta Velocidad. In 2018, Ineco’s traffic management team directed traffic control and performed functional testing during phase 3 of track assembly, facilities and overhead contact line works on all sections. Ineco’s qualified personnel were responsible for comprehensive rail traffic management, which involved directing operations, supervising safety in dangerous areas of the works and ensuring compliance with train safety, construction and testing regulations prior to handover to Adif. The team also managed safety facilities from the CTC located in Granada and was responsible for managing geometric and dynamic testing with laboratory trains to ensure optimum traffic conditions at >10% of the maximum speeds allowed at each point.

The first steps: the construction projects

In 2005, as part of its 2005-2020 Strategic Infrastructure and Transport Plan, the Ministry of Public Works, through a public tender, awarded Ineco the infrastructure and track construction project for the high-speed line between Bobadilla and Granada, part of the Tocón-Valderrubio stretch. The section was designed to allow general speeds of up to 350 km/h and 220 km/h over points. The total length of the section was 14.082 kilometres, with the most significant structures being a 734-metre-long viaduct over the Brácana ravine and the 650 metre Íllora cut-and-cover tunnel. With the project in the home stretch prior to handover, archaeological remains were discovered in the town of Escóznar known as ‘El Pago de El Tesorillo,’ a place mentioned vaguely in a scientific article as the location of undetermined Roman ruins. In order to minimise impact on the area, the railway gradient was raised, and the embankment was replaced by a 150-metre viaduct. The design of El Tesorillo viaduct consisted of five 30-metre spans, a maximum height of 5 metres and detachable beams, in case further excavation is required in the future.

Neolithic village and Roman villa

To reach Granada, at an altitude of 738 metres above sea level, AVE trains have to ascend from 380 metres at Antequera, Málaga, crossing gentle plains interrupted only by the complex geography near the town of Loja, flanked by two mountain ranges and crossed by several rivers and aquifers, where the train line has followed a meandering route that dates back to the 19th century.

It is here when they pass through this town – and until the Loja bypass is built – that fast AVE trains have to slow down to travel along the old conventional track adapted with a third rail, a project carried out by Ineco, as well as the 2.3 kilometres of the access to Granada station.

The company approached this complex passage through Loja by carrying out the platform construction and connection route project, including the construction of a new station, renovation of the track and permeabilization of the route. Ineco also adapted and reinforced three small tunnels and the existing geotechnical structures between them for the passage of the AVE high-speed line and several grade crossings were eliminated and replaced by new access routes.

In the construction of this infrastructure, Ineco adopted measures to eliminate or minimise the impact on the environment and cultural heritage, in compliance with legislation. Many affected heritage sites are defined in the construction project, meaning that corrective measures are taken before the works begin. Other elements are found in the subsoil and are only discovered when earthmoving begins, making it necessary to coordinate all of the archaeological activities.

This was the case of the discovery of a Neolithic village near Antequera that affected the route of the AVE high-speed line. A Roman oven from the 1st-century AD was discovered, which Ineco and Adif turned over to Antequera museum in collaboration with the Regional Government of Andalusia’s Department of Culture and the local city council. Removal, structure consolidation and final transfer works were done by a specialized company, Taller de Investigaciones Arqueológicas. Another important site discovered in Antequera was the ‘Casería Mayorga/Silverio’ Roman villa and necropolis, a discovery that highlighted the economic and demographic importance of the Vega de Antequera region in Roman times. One of the most important conservation measures carried out during the infrastructure construction works was the recovery and transport of the most significant elements of this residential villa complex (its mosaic floors and a sculpture of its owner) to the Antequera Museum.

Platform and track assembly works

Construction of the platform began in 2006, with Ineco and Adif in charge of construction management. Track assembly was carried out in several sections: Antequera-Loja, Gobantes-Bobadilla, Loja-Tocón, Tocón-Granada and Granada station and accesses. In the Antequera-Loja and Tocón-Granada sections, Ineco provided track assembly technical assistance to construction management, while, in the Loja-Tocón section and the Granada station and accesses, the company was in charge of construction management for the platform and track.

The goal of the project was to put the track into service on the platforms that would allow high-speed traffic to take advantage of the longer section compatible with the current arrangement. The Antequera work base was also connected using 1.435 gauge to the new high-speed line in order to facilitate maintenance operations on the Antequera-Granada line during the operating phase.

Signalling and communications systems

Ineco was responsible for technical assistance in relation to the supervision and oversight of project drafting, execution of works, maintenance and upkeep of signalling control points, train protection systems, CTC and auxiliary detection systems, as well as the technical assistance for fixed telecommunications, protection and security facilities, and GSM-R.

When it begins to operate, the line will have ERTMS Level 2. Ineco is currently participating in the dynamic testing of the ERTMS L2 system, as well as ERTMS/ETCS level transitions between the Córdoba-Málaga and Antequera-Granada high-speed lines.

LSB (lateral signalling block) was used with AVE mode ASFA as a backup system to the ERTMS, using audio frequency track circuits and axle counters in mixed track areas. On the conventional line, which will be accessed from Antequera-Granada, an automatic single-track release block was established and the automatic single-track block between Granada and Albolote was adapted.

The facilities that were made available for performing the ERTMS tests included Antequera HS, and Íllora and Granada HS electronic signalling control, with their associated trackside and cabin elements, as well as LSB along the entire Antequera-Granada line; the updating and integration of new equipment for the Antequera Santa Ana CTC; falling objects detectors in elevated sections and tunnel mouths, hot-box detectors, lateral wind detectors and their integration into the remote control of auxiliary detection systems on the Córdoba-Málaga high-speed line; fixed and mobile telecommunications network (GSM-R), fibre optic network, SDH transmission systems, IP/MPLS data network, switched telephone network, etc.; video surveillance and access control and the installation and integration of new CTC equipment into the Antequera control and regulation centre and the centralised control centre in Madrid-Atocha.

Prior to these tests, the Córdoba-Málaga high-speed line was connected via the Gobantes junction for integration into the LZB systems, adapting the field elements, electronic signalling control and existing train protection systems in Antequera Santa Ana belonging to the Córdoba-Málaga high-speed line, due to the new connection of the station to the Antequera-Granada high-speed line and the replacement of the electric signalling control of Granada station with ENCE, integrating the connection of the Antequera-Granada high-speed line.

Energy supply and civil protection of tunnels

In terms of energy systems, Ineco was in charge of technical assistance on works relating to electric traction substations and auto transformation centres, energy remote control and overhead contact lines and associated systems, such as point heating, tunnel lighting and power supply to consumers, in addition to civil protection and safety facilities.

The company was also commissioned to carry out an independent safety assessment (ISA) of the control, command and signalling system, as well as an independent assessment under Regulation 402/2013 (ASBO) of the rest of the TSI subsystems, their interfaces and their secure integration for the commissioning of the line.

Three high-speed stations

Ineco drafted the projects to adapt three stations on the last section of this line to high speed: Antequera, Loja, and Granada. At the Antequera station, the project included a new passenger building, access road, car park, pedestrian connection and track overpasses to connect to the conventional station.

For Loja’s new high-speed station, Ineco was responsible for drafting the project and construction management. It also drafted projects for an underpass between platforms and is currently finalising a project for a footbridge in the neighbourhood of Esperanza. The last works on the station include the construction of the canopies over its central platform.

As for the Granada station, the project for the arrival of high speed included the renovation and extension of its passenger building. The result is a building with a U-shaped layout that brackets the track yard and platforms, which are joined by the head house. The extension is carried out by means of a large canopy that joins the existing and new buildings; it extends and looks out over the plaza to mark the new entrance and is curved to protect the new concourse from the passage of the metro. This outer covered threshold is the hinge point between the existing building and the extension. The eastern façade of the boarding area is transparent to enhance views of the Alhambra and Sierra Nevada.

This report was made possible thanks to special contributions by Pedro Asegurado and Pablo Nieto, specialized railway technicians; Fernando Díez, traffic expert; Javier Cáceres, biologist; Marisa de la Hoz, Diego Martínez, Aránzazu Fernández and Lidia Sainz-Maza, civil engineers; Carlos Montero, Antonio Sancho, Carlos Palomino and Arantxa Azcárraga, architects; Manuel Fernández, electrical engineer; Rafael Soler, mechanical engineer; Javier Millán, telecommunications engineer; Laura L. Brunner, bachelor of physical sciences; Manuel González, industrial technical engineer; Daniel Pérez, signalling expert; David Carrasco, industrial engineer; Fernando Cardeña, communications, video surveillance and access control expert; Javier Barragán, overhead line technician; Rafael Arévalo, energy expert; Francisco Perrino, auxiliary detection system expert; and Manuel Tirado, ERTMS expert.

The purpose of the control of track material supply is two-fold: on the one hand, to ensure that the quality of the material provided meets the initial specifications, and, on the other hand, to make sure that, through control and management of materials, work deadlines are met. Interestingly, in high-speed track assembly works, the actual laying of the track accounts for approximately 20% of the budget, while materials account for 80% (20% ballast, 20% sleepers, 20% rail and 20% track S&C devices). Technical assistance work therefore focuses on two aspects: supply management and quality control, for which factory or quarry production requires supervision and verification, with regular testing upon receipt in accordance with the regulations in force.

The creation of Spain’s high-speed network began more than 30 years ago, and today it boasts more than 3,100 kilometres in service and numerous stretches under construction. Between 1988 and 1990, Ineco began to draft preliminary studies for the Madrid-Barcelona line and the first construction projects started to appear in 1994 and 1995. The Spanish railway infrastructure manager at that time, GIF, commissioned Tifsa –a company linked to Ineco since 1999 and with which it merged in 2010– to undertake the technological definition of the superstructure elements, a contract that, for Moisés Gilaberte, Ineco’s Rail Business director, “was a significant milestone because of its size and importance. Since then, the company has provided support to the government in monitoring the production, planning and logistical deployment of supplies to works and quality control of all materials installed on high-speed lines, making us a European benchmark in track technology”.

From the execution of track assembly work on the 481-kilometre section between Madrid, Zaragoza and Lleida, which opened in 2003, until today, Adif Alta Velocidad, with Ineco’s support, has accumulated extensive experience in the organisation and control of the supply of track materials used on high-speed lines. Spanish industry has successfully adapted to high quality requirements and extremely demanding production and supply deadlines to the extent that it is currently capable of meeting the construction needs of the entire Spanish high-speed network and, in many cases, exports its output, as was the case with some of the material used on the Makkah-Madinah high-speed line in Saudi Arabia.  In Spain, some of the latest track material quality control work has been carried out on high-speed sections such as Venta de Baños-Burgos, León-Variante de Pajares-Pola de Lena, Zamora-Pedralba-Ourense, Plasencia-Badajoz, Monforte del Cid-Murcia, Antequera-Granada and Atocha-Torrejón de Velasco.

From visual inspection, measurement and weighing, to laboratory comparative testing, control of assembly operations and commissioning, the functions of Ineco’s technical assistance include verifying compliance of materials with supply specifications and regulations, monitoring for defects in manufacture, and subsequent transportation, storage and use in works. For this, batches are identified by date of manufacture and company to ensure clear traceability, and samples are taken to validate each batch based on measurements and comparative testing, thus ensuring the quality of the material to be incorporated into the works.

A dossier is opened for each material where information (measurements, comparative testing results, etc.) is recorded and this is submitted to Adif as necessary documentation to commission a line. In the case of track devices, all assembly operations are also controlled, generating a acceptance protocol for each device, documentation that is also essential to commission a line. Ineco’s experts also provide advice on track materials during the design, assembly and operating phases.

Track consists of ballast, sleepers, rail and track devices. All of these elements make up what is referred to as the high-speed track superstructure, and are located on top of the subgrade.

Over the last 15 years of collaboration between INECO’S and Adif’s technicians, more than 1,100 track devices and approximately 700 expansion devices have been checked

Ballast stone and its meticulous inspection 

Ballast is used from the beginning of construction of the railway as a support for the tracks, dampening and distributing the loads transmitted by train traffic, ensuring the stability of the track, enabling the rainwater drainage and facilitating levelling and alignment operations. Ballast is extracted from silica-based rock, preferably of igneous or metamorphic origin. Its granulometry is falls almost entirely into the coarse gravel classification, with most of its broken stone elements measuring between 31.5 and 50 mm.

The required characteristics of ballast are mainly related to shape and hardness in order to obtain good permeability, but with a high degree of compactness and numerous sharp edges on the particles that make it up. The goal is for it to behave like an elastic, but extremely stable, bed. For this, the aim is to achieve the greatest number of contacts between stones, which, together with the high degree of hardness required for the material, means that during installation and operation, breakage and wearing of the material are minimised, and consequently, the geometry of the track superstructure is maintained for as long as possible, thus reducing maintenance operations.

Spain has 45 approved quarries for the manufacture of type-1 ballast, which is the type used most commonly across the railway network. Control of this material begins in the quarry itself and includes a weekly sampling plan depending on production. As a general rule, a complete ballast test will be carried out every 6,000 t of new material. Ineco, in collaboration with a laboratory accredited by ENAC for carrying out ballast tests, analyses the results of a complete test including analysis of grain size, fine particle content, fine content, shape coefficient, minimum thickness of granular elements, particle length, Los Angeles abrasion test and ballast homogeneity. Lastly, ballast tests are carried out during supply to the works to ensure quality and the ballast that is actually supplied is monitored using weighing scales installed for that purpose.

Sleeper dimensions and placement

A sleeper is defined as a transversal component of the track that controls track width and transmits loads from the rail to the ballast. For the construction of high-speed tracks, prestressed concrete monoblock sleepers are used, with pre or post-stressed reinforcement used to precompress the concrete. The type most widely used in high speed, AI-VE, is 2,600 mm long and the minimum mass without anchors is 300 kg.

Quality control work includes acceptance in the factories where the sleepers are produced. In summary, acceptance consists of checking external appearance and traceability, geometric verifications affecting track width, geometric verifications of critical dimensions and principal dimensions and mechanical tests, as well as verification of external laboratory tests required by the technical specification. Once on site, it is important to schedule the supply according to the work plan to avoid unnecessary delays and surpluses.

Rail quality and welding

Once the sleepers are arranged on the ballast bed, the rails are then unloaded from a rail-transport car equipped with a gantry crane.

The rail, as a fundamental element of the track, must have a series of characteristics that allow it to withstand a complex set of forces: its profile, length and metallurgical composition must conform to the requirements established for the track. The rail installed on the tracks of Spanish high-speed lines is profile 60 E1 and grade R260, in accordance with European regulations and Adif’s technical specifications.

Generally, on Spanish tracks, rails are assembled in long welded bars (288 and 270 m), a length that varies depending on the length of the primary bars (36, 72 and 90 m) that make it up in order to reduce the number of welds, which are delicate to perform correctly and generally give worse geometric and mechanical characteristics than the rails, constituting points of disturbance to the rolling of trains which need to be monitored in the maintenance phase. Spanish high speed currently uses 108-m primary bars, which are later electrically welded using a mobile plant. The aim is to maximise the length of the primary rail, making an electric weld using automatic equipment, with no filler metal and minimal human intervention, so that the resulting product resembles a continuously-rolled bar as closely as possible both in terms of composition and defect-free geometry.

The quality control carried out by Ineco on the rails involves, on the one hand, validation at the rail factory (primary bar) and then in the electric welding workshop (welded long bar). For this, geometry and external and internal rail and electric welding checks are carried out, as well as comparative tests in the external laboratory on both elements.

Prior to supplying the rail, the condition of the storage slab, its levelling and the equipment for unloading and installing the rail (gantries and hoists) are checked with the manufacturer and supplier. Once the rail has been deposited on the slab, its arrangement is inspected and a random check of the geometry is carried out using verification templates. Ineco is also in charge of the traceability of the rails supplied to each high-speed line, which is essential for identifying the future physical location of bars produced by the same rolling, which, over time, can lead to the appearance of defects not detected by the usual verifications.

Spanish industry has been able to adapt to high quality requirements and extremely demanding production and supply deadlines in order to meet the construction needs of the entire Spanish high-speed network and, in many cases, exports its production overseas

Control of track devices 

Track devices are essential elements for the operation of the railway because they allow trains to pass from one track to another by means of turnouts, and they absorb movements that are generated in hyperstatic viaducts caused by various factors (temperature expansion, braking effects, rheostatic effects, etc.), the so-called expansion devices, which make thermal contraction and expansion movements compatible with the track superstructure installed on top of them. In Spain, there are four companies that manufacture track devices (two in Asturias and two in the Basque Country), and they provide almost the entire national supply and a significant part of the international supply (Saudi Arabia, Turkey, Argentina, Brazil, Mexico, etc.).

Controls and checks are continuous given that the turnouts used on high-speed lines allow speeds of up to 350 km/h on direct track and 80, 100, 160 or 220 km/h over points, depending on the model, meaning that safety must be guaranteed at all times. The controls on these devices begin by verifying compliance with the main parameters during pre-assembly in the workshop, a task that is formalised with the signing of an acceptance protocol. In addition, supply deliveries and deadlines have to be checked and, once at the track assembly base, the same parameters are reviewed before the device is incorporated into the track.

Track devices may be incorporated while the primary levelling of the track is being done. From there, a topographical survey is carried out during ballast laying and stabilisation phases until the final level is reached. Once the topographical parameters have been verified, an approval report is drawn up. Subsequently, the track device is checked again to ensure that all of its components are in perfect condition and working order, lastly checking compliance with the parameters guaranteeing operation with complete safety. At this point, a works acceptance protocol is issued and this becomes part of the documentation submitted prior to the commissioning of the line.

As for expansion devices, in addition to the work described above, viaduct joints must be measured regularly for different temperature ranges. Based on these measurements, together with the temperature at which they were taken, a progression line is obtained and this makes it possible to determine whether the planned expansion device is suitable, or whether another model needs to be used in its place to ensure the required safety and operating conditions. The extensive experience of Ineco’s staff makes it possible for them to continuously collaborate with track device manufacturers in order to facilitate the evolution of the models, improve performance and reduce costs without affecting in the least the required safety standards. Over the last 15 years of collaboration between Ineco and Adif’s technicians, more than 1,100 track devices and approximately 700 expansion devices have been verified.

This is a key project and the most complex one that Adif Alta Velocidad faces in the entire ‘Basque Y’ network, with Ineco carrying out the construction projects in collaboration with Basque railway company ETS. The result is a set of optimised projects in which the layout design of this network of railway tunnels was finally resolved with the decision to divide it into three sectors instead of the initial four.

UDALAITZ TUNNEL. Part of the geomechanical profile of the Udalaitz Tunnel (Sector 2).

The Ministry of Public Works plans to complete this high-speed line, which connects the centre and southeast of the Iberian Peninsula via Madrid to the Basque Country and France, in 2023. Last July, the contract was awarded for the last of the three stretches that make up the Bergara junction, which covers 21.2 kilometres and is dominated by tunnels and viaducts where the three branches that link the cities of Vitoria, Bilbao and San Sebastián meet. In total, 14.8 kilometres of single-track and 3.6 kilometres of double-track tunnel have been designed. The tunnels will be excavated using conventional methods with four points of attack.

The Bergara Junction, with construction projects prepared by Ineco, is the most complex project that Adif Alta Velocidad must undertake in the entire ‘Basque Y’ network

All of the sectors have been designed for mixed traffic, with a maximum speed of 220 km/h and minimum speed of 90 km/h. To allow the tunnels to operate, each one has been designed with an independent drainage system for the collection of hazardous substances and contaminants. The project also includes all of the necessary safety measures, including 22 evacuation galleries between tunnels, as well as walls, drains, environmental integration, areas for ancillary facilities, repositioning of rights of way and affected services, inert waste dump and any other actions necessary for execution. After the works have been completed, the land will be restored to its original state.

‘BASQUE Y’ HIGH SPEED. Platform construction project. / PLAN_INECO

The project is co-financed by the Connect Europe Facility (CEF) and the European Investment Bank (EIB).

The drafting of the projects involved optimisation of previous construction projects:

• Shorter timescales.
• Improved tunnel design in complex geological areas.
• Improved instrumentation measurements for the monitoring of works.
• Landfill management.
• Adaptation of designs to environmental protection requirements.
• Tightened budgets.

CRUCIAL CONNECTION FOR THE ‘BASQUE Y’

The Bergara interchanges connects the three ‘arms’ of the ‘Basque Y’, with 50% running through tunnels, 10% on viaducts, and the remaining 20% above ground.

MAP_BASQUE GOVERMENT

The viaduct and the European mink

The Kortazar viaduct, located in sector 3, consists of a continuous beam deck made from pre-stressed concrete and embedded into two V-shaped piles that act as fixed points. The project is the result of a study of several configurations that needed to take into account the impact of the central piles on both the N-636 road below and the habitat of a colony of European mink. In the image, the longitudinal cross-section of the Kortazar viaduct.