The final phase of the major investment by Network Rail to increase capacity on the routes in and out of London Waterloo station is nearing completion with the refurbishment and modification of the former Waterloo International Terminal (WIT), originally used by Eurostar trains but closed since November 2007 when the service was transferred to St. Pancras International. The work is being project managed by the Wessex Capacity Alliance, a partnership of Network Rail, Skanska, AECOM, Colas Rail and Mott MacDonald.
During August 2017, Platforms 20 to 24 were put to temporary use for domestic services, but without the full functionality now being provided, to allow closure of Platforms 1 to 10 for the lengthening and reconstruction of Platforms 1 to 4 (issue 156, October 2017). After that temporary closure, Platform 20 remained in use for Windsor line services, but Platforms 21 to 24 were closed again to allow for the major works now nearing completion.
Work is taking place below, on and above these platforms with a complex mix of activities. The most apparent of these activities is the provision of a major new structure – the ‘infill’ roofing between the original station roof and the WIT roof. But, apart from this, there is modernisation of the platforms, repairs to the WIT roof, installation of lifts, escalators, stairways, ramps, emergency exits and gatelines, refurbishment of the ‘orchestra pit’, completion of the permanent features of the new link bridge and fitting of all mechanical and electrical services. That’s quite a list!
The design and finish of the ‘infill’ roofing has obviously been a major architectural challenge. The original station roof is a fairly conventional arrangement of main long-span trusses supporting smaller apex bays carrying the glazing. The WIT roof is an iconic structure in the form of three-pinned arches arranged at right angles to the track/platforms.
The gap between the two roof structures arose as a result of the desire to develop and utilise the ‘orchestra pit’, of which more later.
The gap to be infilled is approximately 15 metres wide by 60 metres in extent. The accepted design is a series of inverted triangular steel trusses, supported on two tall and tapering steel columns and also partially on the top member of the ‘gable-end’ truss roof structure. This arrangement is intended to hopefully blend the two roofs, but will, in reality, only be seen by those observers keen to look skywards with craned necks.
Externally viewed, however, planning stipulations by Lambeth Council required the infill to be in the form of a rectangular box, being the outer and upper shell of glazing. This is what local residents in adjacent high-rise blocks of flats will see.
The ‘foundations’ for the new roofing supports required extending the steelwork down well below concourse level. The roof is supported by the original station masonry arch structures to the east (Platform 19), by the WIT structure in the centre, and on new foundations over the Waterloo & City lines to the west (Platform 24). The reuse of the existing structures around the London Underground control room had to be suitably tested and reinforced to withstand these new loads.
The roof infill was designed by the Wessex Capacity Alliance. The placing and fixing of the steelwork, which was fabricated by Bourne Steel, is being facilitated by a significant temporary steel structure, a kind of falsework (painted yellow for distinction – see photographs) and the ingenious use of a range of long reach mobile platforms for access to locate and bolt and/or weld connections. Leading specialist building envelope contractor Prater is carrying out the glazing.
Passenger facilities and circulation
The ‘orchestra pit’ referred to earlier is a development of the sunken area below the main concourse level, which was originally used as the Eurostar passenger waiting area. At the rear was the booking office and Eurostar offices/stores. At the front were the check-in, security and passport controls. This whole sunken area has been enlarged by modification of the floor slab (more accurately, the platform support structure) to create a larger passenger circulation space – the Coleman Group carried out all the general demolition work, RGL Services the specialist hydrodemolition and the Kelly Group did all the new concrete works.
The creation of the ‘orchestra pit’ is key to the provision of great flexibility for passenger transfer and circulation. For passengers wishing to gain access to the new platforms, either from any other platform or from concourse level, there is a new broad link bridge (constructed by Kilnbridge) taking them straight to the new Platform 20/24 concourse with its gateline, train information boards and other services.
For those transferring to/from London Underground, there is a broad, new flight of steps from concourse level to the orchestra pit level and then three new escalators leading to the London Underground subway level. And for those transferring directly between national rail services on Platforms 21/24, there are escalators between platform and orchestra pit levels.
There are also lifts between these levels, making use of old WIT lift shafts but with new equipment installed by Stannah Lifts, which is also providing two completely new lifts between the orchestra pit and LU subway levels.
At the foot of the island platform escalators, gatelines enable access/egress directly to orchestra pit level and thence on through to LU subway level. All of this new equipment and structural alterations, including the very imaginative development of the orchestra pit, will enable smooth and flexible passenger circulation while minimising any further congestion to the original main station concourse.
To facilitate direct access between Platforms 19 and Platform 20, a two-section ramp and a stairway have been provided. This is effectively a new island platform, but with one half at the original old station level and the other at WIT level. This is the only location where the new interface has had to be addressed in this way.
Some modifications to Platforms 20 to 24 have been necessary in putting them to their new use.
These platforms have been shortened by 50 metres at their country ends so as to accommodate a new switch and crossing layout, installation of which also necessitated major structural modifications of the viaduct beneath. This new layout gives the flexibility to operate a service of 20 trains per hour, compared to the five or six trains per hour in the time of Eurostar operation.
Add to this increase in trains per hour the fact that a fully occupied commuter train will have around 1,500-1,600 passengers aboard, wheras a Eurostar train has a capacity of 750 passengers, and it can readily be appreciated what a step change in capacity the WIT work is providing
As well as being shortened at the country end, the London ends of Platforms 20 to 23 have also been shortened by 50 metres to create the passenger concourse area. Even with these length reductions, all the new platforms can take 12-car trains.
In the location vacated by the shortening of Platforms 20 to 23, a spacious 50-metre-long new concourse has been formed using a voided concrete slab with polystyrene infill.
Each new island platform (21/22 and 23/24) has new escalator wells and stairwells. All of these have required significant structural modification and reconstruction of the original platform slabs. Conversely, some platform openings from WIT days that are not now required have had to be structurally infilled. The works to modify various concrete structures are being carried out by Kelly Formwork (UK).
Although the platform edges originally had tactile strips, these were not of the standard now required to warn visually impaired passengers of the edge risk. Previously, passengers would only have had access to the platforms whilst a stationary Eurostar was already platformed. Now, they will be exposed to the greater hazard of moving trains. Therefore, all the coping slabs have been replaced with an integral tactile strip to the correct standard. Despite the platform shortenings, this work has still amounted to the placement of 1.5km. of new copings.
Rail Engineer was escorted on a route through the impressive catacombs, a network of major brick arches, beneath Waterloo station to view the works. Old WIT mechanical and electrical services are being stripped out and being replaced by new cabling and ducting for communications infrastructure, fire systems, public address, lighting and ventilation.
There are extensive plans for releasing large areas under the new platforms for retail uses by private developers. It is understood that this will commence soon after the current project to open the new platforms is completed.
Tiling of all walkway and concourse areas is ongoing and the finishes and parapets for the link bridge are being worked on.
The new platforms are scheduled to open for passenger use on 9 December. This will provide immediate benefit to the operation of the station with the existing services. No doubt, when a new timetable comes into force next May, the full flexibility and capacity improvement gained from the new platforms will become even more apparent. The Southwestern train planners will have a major new asset, enabling them to diversify and improve the train service pattern optimally.
Prior to these capacity improvement works, Waterloo station was handling approximately 96 million passengers a year. After commissioning of the WIT platforms in their new role, which will be the final element of the overall project, that capacity will have been increased to 120 million passengers.
To achieve this, the cost of the change in use of the WIT platforms to their new future role is estimated at £170 million. That sounds like very good value.
Read more: An update on the West Midlands Metro