Visiting railways outside the UK on the IMechE’s technical tour always provides fascinating insights. In May, this year’s tour visited the Netherlands, Germany, and France. The next issue will have a full report on this tour. In the meantime, for our station focus issue, this feature describes the major station projects at Amsterdam and Stuttgart which were amongst the highlights of the tour.
With its 11 platforms, the through station at Amsterdam Centraal has 73 million passengers per year. Stuttgart Hauptbahnhof is a terminal station with 16 platforms that has 93 million passengers a year. This is comparable to the traffic at London Liverpool Street, the UK’s busiest station. Both these projects will increase passenger capacity though in quite different ways.
Trains, trams, metros, buses, and bikes
When Amsterdam Centraal station opened in 1889, it replaced three terminal stations. The station was built on three interconnected artificial islands in the IJ waterway on the north side of the city centre. As a result, it required the sinking of 8,000 wooden piles. The station was designed by Pierre Cuypers and so resembles the city’s Rijksmuseum for which he was also the architect.
When built, the station had five through platforms and one bay platform. In 1924, the station was provided with additional platforms to give it 10 through platforms, most of which were subsequently lengthened to accommodate two trains simultaneously. As a result, the station now has 10 through platforms and one bay platform. Before the start of the current project, the station’s track layout was not much different from that of 1924. This includes four through track bundles comprising three tracks with a middle track that originally provided for the release of steam locomotives.
This gives it a total of 15 tracks numbered from south to north with Number 1 being the bay platform. The tracks at the station are generally operated as two terminating tracks, albeit without buffer stops in the middle, as most trains reverse directions when they terminate at Amsterdam Centraal.
Centraal station is now a major transport hub served by 11 tram lines, ferry services, a new bus station on the north side of the station, which was opened in 2015, and four metro lines. The most recent metro line, opened in 2018, necessitated the construction of a metro station under the central pedestrian tunnel. It also offers underwater storage space for 11,000 bicycles. During the last decades much has been done to improve the pedestrian flow at the station, including the widening of the existing pedestrian tunnels and the construction of new passages under the station.
Wider platforms, fewer tracks
Passenger numbers at the station are expected to grow from the current 200,000 a day to 275,000 a day by 2030. The work at Centraal station is part of a national project of upgrades to increase rail capacity on major routes by replacing the current 15-minute clock face timetable with one that provides trains every 10-minutes. This will require the station to accommodate an extra 15 trains per hour.
During the technical tour, Lee Verhoeff, station policy advisor for Dutch rail infrastructure manager ProRail, explained how this capacity increase was to be provided. Surprisingly, the answer was fewer rather than more tracks. This is because the key capacity constraint is passenger flow. Hence the widening of the current island platforms is essential, and this can only be achieved by eliminating the middle track between the platforms. This makes it possible to increase the island platform width, typically from 8.6 to 13.5 metres.
Other improvements to the pedestrian flow include widening the platform exits and the eastern pedestrian tunnel to three times its current 4.5-metre width. The entrance to the western tunnel has recently been enlarged and made fully accessible for people with reduced mobility. Extra bicycle storage next to the eastern passenger tunnel is to be provided with space for an additional 8,500 bicycles.
The removal of the middle tracks provides an opportunity to rationalise the station track layout which includes the removal of the complex double switches on the middle tracks. This requires a dive-under at Dijksgracht, two kilometres east of the station.
On the east side of the station, four life-expired steel bridges over the Oostertoegang on the station’s eastern side need to be replaced over a five-year period starting in December 2024. A fifth concrete bridge of more recent construction has also been replaced so that the throughfare under all of the bridges can be widened. The replacement bridge sections are being shipped to the Oostertoegang on flat barges. They are put into position using a jacking system with a four-metre lift that can rotate the bridge components by 90 degrees.
Progress to date
In March, ProRail completed the first phase of this project by renewing tracks 14 and 15 and replacing the first Oostertoegang bridge. The second phase of construction involves the renewal of tracks 11 and 13, removing track 12, widening the island platform between tracks 13 and 14 and renewal of the second Oostertoegang railway bridge.
In this way, the station project is working from North to South. As the current service can be delivered with eight tracks, it is acceptable for either one island platform or one track bundle to be out of service at any time.
In April, two tracks over the new fly-over at Dijksgracht junction were opened. In June, the improved entrance to the western passenger tunnel re-opened. This now has 30 access gates instead of the previous 19 gates to resolve congestion at this location.
The project to remodel Amsterdam Centraal station is planned to be completed early in the 2030s when there will be a three-week closure of the station throat. The anticipated final cost is expected to be €1 billion.
International traffic
Amsterdam Centraal station serves four international rail routes including three daily Eurostar services between Amsterdam and London. Eurostar plans to increase this to five daily services in 2026. In April, a new UK terminal between the central and eastern tunnels was opened at the station which provides security and border facilities to process 650 passengers per train. With further passenger boarding at Rotterdam, this will accommodate around 800 passengers per train between the Netherlands and London.
However, due to the planned increase in Dutch domestic train services, once the station enhancement works are completed at Amsterdam Zuid, there are plans to move international services to this station which is at the southern edge of the city.
Stuttgart 21
The new Stuttgart station is part of the much bigger Stuttgart 21 project which includes two other new stations, 57km of new railways including a 25km high-speed line, and 30km of tunnels. It has similarities to the HS2 project. When construction started in 2010, Stuttgart 21 was expected to be open in 2019. The planned opening date is now late 2026. Costs have risen from an estimated €4.5 billion in 2009 to €11.5 billion. It has been widely criticised and has attracted environmental protests. Yet, unlike HS2, it is being delivered in full.
When work started in 2010, many protesters were injured when the police used water cannons and batons as they protested against the removal of trees by the station when work started. An inquiry about how the management of these protests included a recommendation that there should be better promotion of the project’s benefits. In response to public opposition to the project, a state referendum was held in 2011 in which 59% of voters voted in favour of the project.
Infoturm Stuttgart (ITS) is the organisation set up to promote the project. A YouTube video, produced in 2012, is one such promotion. Its promotion of the project includes diagrams explaining why through stations are more efficient than terminal stations.
In 2020, ITS opened a six-floor exhibition tower which explains all aspects of the project using models, digital content, and virtual reality. The technical tour visited this tower and went on one of the public tours of the station construction site that ITS offers.
Remodelling Stuttgart
Stuttgart Hauptbahnhoff is a 16-platform terminal station. Its tracks from the south, north, and east converge into a complex 1.5km elongated station throat which approaches the station from the northeast. This has 255 switches and some grade separated junctions. The Stuttgart 21 project will replace this station with an underground eight-platform through station below the current station.
Four tunnels have been constructed to connect the new station to the tracks from the north and east. One of these tunnels, the 9.5km Fiddler tunnel, takes tracks to a new station at Stuttgart airport. This is a high-speed line which is extended by a further 15km to Wendlingen where it will connect with the new high-speed line to Ulm.
The new station will have no connection to the track from the south which carries trains from Zurich and so when Stuttgart Hauptbahnhoff is abandoned, these trains will terminate at Vaihingen, 8km south west of the city centre. There are plans to build an 11km tunnel to allow trains from the south to reach the new Stuttgart station via the new airport station. However, this will not open until the early 2030s.
Information provided by ITS shows how through stations are more efficient than terminal stations within minimal conflicting moves and higher approach speeds. Thus an eight-platform through platform can replace a 16-platform terminal station. In addition, the journey time of trains passing through Stuttgart will be reduced by 10 minutes or so as they will no longer have to change direction at the terminal station.
As well as transforming the local rail network, Stuttgart 21 will dramatically change the city. Once the new station becomes operational, an 85-hectare, 2.2km swathe of land (half the size of London’s Regent Park) will be released for the city’s largest urban development project. This will provide parks, affordable housing, schools, sports facilities, and cultural institutions, as well as the new Mittnachtstrasse S-Bahn station.
Touring the new station
When the technical tour entered the station, the immediate impression was of a roof with no straight lines made up 28 chalice-shaped supports and 27 ‘light eyes.’ Of these, four are flat units 17.5-metre in diameter and the remainder are 21-metre diameter raised 4.3-metres high. These provide 4,750 sq metres of glazing made up of 3,915 multi-pane glazing units. These units, together with white walls, reduce the need for artificial lighting and are part of the station’s energy efficient design that does not rely on electricity for ventilation, heating, and basic lighting. It took three months to construct each chalice support which required more than 80 large-format formwork elements, 750 tonnes of concrete, and 350 tonnes of steel reinforcement.
At the time of our visit, the trackwork appeared to be complete, the platforms were substantially complete and electrification conductor bars were being installed. The eight platforms are 447-metres long and will be accessed by 15 lifts and 28 escalators. Vibration resistant track fastenings were evident.
One thing apparently missing at the station were signals. This is because the core Stuttgart 21 lines will be ETCS signalled and all trains operating through it will be ETCS equipped.
Part of the tour took the group inside the 100-year-old Bonatzbau station building to see how it had been internally gutted as well as the arrangements to preserve its striking façade. When work is complete, the building’s 160-metre-long hall will provide easy access to the new station below. It will also have two new levels with shops and facilities for travellers as well as a modern hotel.
S-Bhan
Stuttgart’s 215km suburban railway network, the S-Bhan, comprises 83 stations on seven lines. It serves the Stuttgart Region’s population of 2.7 million and carries around 400,000 passengers per day. Its Stuttgart Hauptbahnhoff station is under the concourse at the end of a 2.6km tunnel which emerges just beyond the terminal station’s platforms.
As part of Stuttgart 21 a new station has been constructed at Mittnachtstrasse, 1.5km from the Hauptbahnhoff. This will serve the area of land that is to be reclaimed once the old station’s tracks have been abandoned, and is expected to have 20,000 passengers per day. The construction of this new S-Bahn station requires an extension of the S-Bahn tunnel under Stuttgart Hauptbahnhoff and a new railway bridge over the River Neckar.
This new route will increase the reliability of S-Bahn services as it will give them dedicated tracks through the city. Currently, the S-Bahn currently shares tracks here with regional trains which causes delays.
Ulm high speed line
A project linked to Stuttgart 21, but not part of it, was the construction of a 58km high speed railway between Ulm and Wendlingen where it will connect to a high-speed line constructed as part of the Stuttgart 21 project.
This line has eight tunnels totalling 27km in length bored through the difficult geology of the Swabian Jura mountains. The 85-metre-high Fistal viaduct is between two of these tunnels. This has two single track spans of 472 metres and 485 metres. This line has a maximum height of 750 metres above sea level and a maximum gradient of 1 in 32. It has a station at Merklingen, 24km from Ulm.
After this high-speed line was approved in 2007, construction started in 2010. The line opened in December 2022 when it reduced the journey time between Ulm and Stuttgart from 56 to 42 minutes. When the Stuttgart to Wendlingen high-speed line becomes operational, this journey time will be further reduced to 27 minutes.
This line was constructed at a cost of €4 billion. As it is part of the Paris to Budapest Trans-European line. The European Union provided funding for 50% of the project’s planning phase and 10% of its construction costs.
Stuttgart Digital Node
Concerns about Stuttgart’s S-Bahn punctuality resulted in an S-Bhan European Train Control System (ETCS) study which was published in 2019. This concluded that ETCS and Automatic Train Operation (ATO) could reduce headways by around 20% in the congested S-Bahn core. It was also the impetus for the Stuttgart Digital Node project (Digitaler Knoten Stuttgart, DKS) as the S-Bhan core needed new signalling anyway and the new lines being built for Stuttgart 21. As a result, DKS became one of three areas pioneering ETCS in Germany, the others being Koln to Frankfurt and Munich to Hamburg.
When Stuttgart 21 lines are opened, the core services will be ETCS signalled and all trains operating through the new Stuttgart station will be ETCS equipped. Adjacent areas will have a signal overlay to accommodate freight traffic which is not yet fully ETCS equipped. As a result, there will be 125km of track carrying 1,700 ETCS signalled passenger trains a day.
This has required 333 vehicles to be retrofitted with ETCS in a programme that started in March 2022. Of these vehicles, 215 were S-Bahn trains for which, in 2021, Alstom secured a €130 million contract to install ETCS and ATO.
Initially, the programme requires ETCS only to be operational. From 2027 onwards, ATO operations will commence to give consistent braking and acceleration profiles. This will be followed by the introduction of a Capacity and Traffic Management System which will continuously optimise operations using the precise positioning information provided by ETCS.
By 2030, it is envisaged that the entire region with its 500km of track with be ETCS signalled after 50 old interlocking systems have been replaced. By this time, it is also hoped to provide these lines with the Future Railway Mobile Communications System (FRMCS).
Cost and benefits
With the Stuttgart 21 initially planned to open in 2019 and costing almost three times its original estimate it is not surprising that press stories have described it as an “$11 billion rail disaster” and “Germany’s latest transport fiasco”. Project sponsor Deutsche Bahn considers that the reasons for the cost increase include:
- A sharp rise in construction inflation.
- A difficult global environment.
- The uniqueness of the project.
- Lack of competition due to weak tenderers response.
- Complex geological conditions.
No doubt there are other reasons. However, whether it is the complete failure that press reports suggest depends on the realisation of its benefits which such press reports rarely mention. In the UK, the Edinburgh Tram and Crossrail projects also attracted much negative comment for being late and over budget, yet the benefits of these projects are now generally accepted.
It is to be hoped that once Stuttgart’s new railway network is operational, its benefits will be apparent to the city’s population and that they will be glad that they voted for it.
Image credit: David Shirres