London Overground’s five-car extension: ‘A three-year programme delivered in 18 months’
Source: Rail Technology Magazine Dec/Jan 2014
Huw Edwards, head of programme delivery at London Overground, speaks to RTM about its ongoing capacity improvement programme (LOCIP), including the introduction of five-car services and associated upgrades to depots, sidings and signalling across the network.
London Overground is an undisputed success story for the rail industry, showing how good project management, attractive rolling stock and clever branding can unleash huge amounts of latent demand.
But passenger numbers have been growing faster than the service’s ability to cope, necessitating upgrades to ensure it is ready for the future and a growing London, and to try to deal with overcrowding.
In 2007, at the end of the previous Silverlink DfT franchise, passenger numbers stood at around 33 million a year. But in 2013, under London Overground – run as a concession let by TfL to LOROL, a joint venture of MTR and DB/Arriva until 2016 – that figure rose to 135 million.
Huw Edwards, London Overground’s head of programme delivery, told RTM that the growth has been due to suppressed demand, but also regeneration in north-east London especially, such as in Hoxton and Haggerston.
The short to medium term solution is a fleet extension for the Class 378 Capitalstars, from four-car to five, for all London Overground routes except Gospel Oak to Barking (the electrification of which will allow the introduction of higher-capacity trains at a later date).
Edwards called the extension “readily deliverable” – and the £88m order for 57 new carriages was placed with Bombardier in Derby under an option built into the original 2007 rolling stock contract, following approval from the TfL board in February 2013.
But preparing the network for the longer trains has been a bigger job, requiring platform extensions, depot and sidings modifications and signalling works.
Of the £321m London Overground Capacity Improvement Programme, roughly £174m is capital expenditure on the fixed infrastructure (the rest is the cost of the new rolling stock and alterations to the existing fleet, plus operations and maintenance over ten years).
Platform extension works on the East London Line started at Highbury & Islington, Canonbury and Surrey Quays in December 2013, with another nine due to be extended between February and June 2014. At some stations, a full platform extension to allow ten doors to open has not been possible; Wapping and Rotherhithe will have to remain at eight door opening, with passengers in the back car told to walk to the next doors, while Canada Water will get a compromise nine-door solution. Edwards said: “Canada Water is a very big interchange for us; we want to do as much as we can. We’ve found an affordable solution which takes us to nine door. To go to ten door would be a massive solution involving part-demolition of the bus station and a major civil engineering project. Yes, potentially there is a business case for that – but that solution isn’t deliverable in the timeframe the mayor wants.”
At Whitechapel, selective door opening will apply until Crossrail is complete. Cleshar is the contractor for these works. “When Crossrail concludes at Whitechapel, a set of temporary overbridges and secondary means of escapes will disappear and the platform lengths for the ELL become that much longer,” Edwards said. “That means we will go to five-car door opening in two or three years’ time at Whitechapel.”
Considering that London Overground seems willing to implement selective door opening when necessary, RTM asked Edwards whether TfL ever considered saving money by selecting that option rather than platform extensions at other stations.
He said: “We took the view that we don’t see passenger numbers getting any less, and therefore where it is relatively straightforward to build, we would – and it is, in the majority of areas. In the south east in particular, platform extensions are going in left, right and centre, and many of them are much bigger ours, the 12-car extensions for example. The answer is, yes we did look in the initial stages whether we’d use selective door opening at a larger number of locations, but we made a business decision to deliver 10 doors wherever we feasibly could.”
The North London Line extensions and disused platform reopenings are simpler; 17 of these will take place between February 2014 and February 2015. Dyer and Butler is to undertake these works.
On the West London Line, platforms on the Clapham Junction to Willesden Junction route will be extended by Network Rail under their eight-car works for Southern, by March 2014.
Train storage, maintenance and signalling
Sidings and depot facilities have also had to be altered to cater for the longer trains.
A major part of the project is Silwood Triangle, where 10 trains will be stabled. It was chosen because London Overground already owned the land, and because it is close to the New Cross Gate depot. The site, in north Lewisham, needed full planning consent – but Edwards told us that achieving this was better than plumping for a sub-optimal site just to get around the difficulties associated with the planning process.
Work at the site began in April 2013, and should be finished by April 2014. It includes revisions to track alignment, new track and walkways, infrastructure for the signalling, and new staff welfare buildings, fencing, car parks and access roads.
Edwards said making use of the Silwood site was a “good win” for London Overground, adding: “There was a discussion about utilising Network Rail sidings down towards the Norwood Junction or West Croydon, but we’ve gone for sidings near our central core – it’s a turnout off our infrastructure that London Overground owns and maintains. It’s a piece of scruffy scrub land which was light industry and scrapyards, very much brownfield, which we’ve redeveloped in a big way.”
Cleshar is the contractor for the majority of the works in the Silwood Triangle.
There are also ongoing depot reconfiguration and station works at New Cross Gate, being delivered by Spencer: extension of the train maintenance shed northwards; extension of the wheel lathe/heavy cleaning shed northwards; changes to the interior layout of the sheds to accommodate the longer trains; alterations to the bays used to store and maintain the trains to stable 13 five-carriage trains instead of 21 four-carriage trains; and modifications to other equipment within the depot so the longer trains can be maintained and to allow the trains to be converted from four to five carriages on site. These works will be complete by October 2014.
The headshunt at New Cross Gate station is also being extended.
Separately, the Willesden Junction train maintenance depot is being extended towards the station, and London Overground is also deciding on a new stabling/cleaning facility to accommodate 12 five-car trains in north London.
These works require extensive signalling changes at the depots and stabling facilities, and linewide alterations including the moving of starting signals and stop markers, the relocation of axle counters, and modifications to the Train Protection Warning System (TPWS) and Automatic Warning System (AWS). The signal changes will have a “slight impact” on train timetabling, meaning there will be consequent changes to the Train Describer (TD), Customer Information Screens (CIS) and Automatic Route Facility (ARF).
The first longer train enters service on the East London Line in late 2014. In total, 29 trains are being extended on the ELL, one a week for just over half a year.
Edwards said: “The insertion of the fifth car will happen at New Cross Gate, unlike when we went from three-car to four-car a few years ago, when it was done at Derby. To reduce outage time, we’re going to take the unit out of operational service for a week, insert the fifth car, fully commission, fully test, and send it back out into operation.”
Of course, all the fixed infrastructure works have to be ready for that first extended train.
London Overground will also need new drivers, because although it’s an extension rather than expansion, Edwards said changing stabling arrangements means changing driver rosters and a need for more drivers.
The main marketing campaign promoting the five-car extension to passengers will begin in summer 2014.
Commenting on the tight timescales of this project, Edwards told us: “When compared to a traditional DfT or Network Rail programme of work, the pace of delivery here is significantly faster. We’ll bring in the first fifth car at the end of 2014, when we didn’t gain board approval to do the work until February 2013. I often say it’s a three-year programme of work delivered in 18 months.”
That means taking risk-based decisions along the way, such as buying the switches and crossings seven months before detailed design was actually completed. “They become a fixed point,” Edwards said, “so we said ‘right, we’ve ordered the S&C, everything has to fit around them’. That’s how London Overground has developed, making risk-based management decisions and design decisions along the journey based on the information known at the time. We’ve been successful in doing that.”
Edwards acknowledged that over a 20- or 30-year timeframe, the five-car extension alone will not be nearly enough to offer the capacity required, although Crossrail will help from 2018.
But the Class 378s can’t be configured to run in six-car formation, so Edwards said the next opportunity for serious capacity improvement after this extension would be at fleet renewal time in the mid-2020s.
Until then, LOROL could run additional train services – going from 16tph on the East London Line core to 18tph, for example. Going beyond that would require ATO (automatic train operation), Edwards suggested, copying the example of the Thameslink core, Crossrail, and London Underground.
He told RTM: “If we stretched and sweated the fleet, we believe we could be running an 18tph service between Shoreditch and New Cross Gate. But the reality is, that’s not where demand is – the demand is south. The demand is for bringing passengers up from the Crystal Palace, West Croydon areas into the central core. So therefore [we are in a] tricky position; that’s where the demand is, that’s where the business case is – unfortunately that’s not where the paths are…so the next discussion to be had with the industry is ‘can we sweat two additional paths south of New Cross Gate’.”