Another vital step in the opening of the Elizabeth line has taken place, but one which has not been widely publicised and to which most passengers will be completely oblivious. With no public fanfare, Transport for London’s new Old Oak Common Depot has come into service as the maintenance base and main train-crew facility for the Elizabeth line trains. Rail Engineer was given a preview of the new state-of-the-art depot with a tour hosted by Howard Smith, operations director for TfL Rail and the Elizabeth line.

Welcoming the progress made since work began four years ago, Howard stressed the importance of the new depot: “As home to the Elizabeth line fleet, Old Oak Common will be vital in helping us maintain our 70 brand-new trains over the years to come.”

Many of the new Class 345 Bombardier Aventra Elizabeth line units are already stabled at the depot and several driver training and technical testing trips are currently being run each day. From 20 May, TfL takes over operation of local services between Paddington and Hayes & Harlington as well as the Heathrow Connect service, although for the time being this will continue to be operated by the existing Class 360 units.

The Class 345s will soon take this service over too, but the depot will truly come into its own in December, when Elizabeth line services start to operate from Paddington to Abbey Wood. The existing Shenfield to Liverpool Street service will run through the central London tunnels to Paddington from May 2019, with full operation through to Reading due in December 2019.

Solar heating and photovoltaic panels make the depot roof a valuable resource.

Solar heating and photovoltaic panels make the depot roof a valuable resource.

New depot for new trains

Old Oak Common will be the maintenance centre for the whole fleet of 70 nine-car units, with up to 42 located there at any one time. Other stabling facilities will be located at Ilford, Shenfield Gidea Park, Plumstead and Maidenhead.

Bombardier will operate the facility as part of a 32-year construction and maintenance package awarded in 2014. Bombardier’s latest Automatic Vehicle Inspection System (AVIS) will be used to scan and analyse trains as they enter the depot, reducing the overall time needed for maintenance and increasing reliability. As units enter the depot, laser and camera equipment will automatically check wheels, brakes, pantographs and other equipment to identify where attention is needed. The system can even spot graffiti!

Andy Derbyshire, head of UK Projects at Bombardier Transportation, sees the depot as a showcase for the new rolling stock. “Our British-designed and built trains are transforming journeys between Liverpool Street and Shenfield and are to do the same between Paddington and Hayes & Harlington. We are really building momentum towards the launch of the Elizabeth line in December.”

Bombardier employs some 80 maintenance and testing staff at Old Oak Common currently, including eight apprentices. This will increase to 110 by the summer, including a further eight apprentices.

Taylor Woodrow, part of the Vinci Group, was appointed as principal contractor for the design and construction of the new depot. Fred Garner, sector director – rail at Taylor Woodrow, explained the process: “The tender specification laid down a lot of the requirements and Bombardier added others. Taylor Woodrow designed the depot and has delivered it with relatively little change to the bid.

“I believe that one of our key strengths was the development of the advanced environmental package. A special team put together a detailed package with impressive sustainability gains, in line with the Mayor of London’s Transport Strategy. The environmental systems have already won several awards.”

Over 30 per cent of the depot is powered by an innovative hybrid renewable energy system, integrating ground source heating and cooling from a combination of 250 energy piles and fifty bore holes each 150 metres deep. Three different types of thermal technologies are used to help control the temperature of the main depot building. Throughout the depot, there is some 40,000 square metres of underfloor piping which heats the facility in winter and cools it in summer, designed to maintain a comfortable and relatively constant 12 to 14°C temperature, whatever the weather outside.

Up on the roof, there are 140kW thermal solar panels, along with 1,500 square metres of photovoltaic panels. And, of course, rainwater is harvested and recycled. Old Oak Common is the first rail depot in the UK to introduce all these environmentally friendly measures together. The full integration of the separate systems is expected to save TfL over 500 tonnes of CO2 each year, as well as significantly reducing running costs.


History

The extensive Old Oak Common site has been in railway use since 1906 when the engine shed and carriage depot, designed by George Jackson Churchward, opened to serve Great Western Railway services from Paddington.

The new depot is located at the north side of the site near the Grand Union canal, in the area which once housed the famous and much-photographed western turntable, the last of the three on the site.

The last remaining parts of the old depot are awaiting demolition to make way for the new HS2 station, which will extend to within a few metres of the TfL depot.

Before the new depot construction started, the site also housed the factory used to fabricate the concrete ring sections for the Crossrail tunnels.


The simulators replicate the Elizabeth line driving experience, here 'arriving at Stratford'.

The simulators replicate the Elizabeth line driving experience, here ‘arriving at Stratford’.

First class facilities

Entering from Old Oak Common Lane is still very much going onto a construction site, with work underway clearing the earlier site buildings and finishing construction of the northern part of the stabling sidings. But across the access road stands the fine new depot building, faced by an impressive array of offices. This smart, modern accommodation includes the base for some 180 drivers employed by MTR Crossrail, as well as housing Bombardier and TfL staff. MTR Crossrail will operate the Elizabeth line on TfL’s behalf.

The facility is a far cry from train crew accommodation of the past, with comfortable climate-controlled rooms. Driver training is also carried out here, with classrooms and two Sydac driver simulators. Around 25 per cent of a driver’s training is carried out on the simulators, which replicate exactly the cabs of the Class 345 units. The trainer in the adjacent control room can call up a range of weather conditions, equipment failures and other scenarios as a valuable supplement to training out on the line.

At the London end of the offices is the depot control room. With a good overview of the outside sidings, this is where all train movements are controlled, including the vital interface with Network Rail. The depot signalling is a GE ElectroLogIXS system, designed and built by Atkins. Although widely used in the USA, and with more than 7,000 installations worldwide, this is the first depot system and the most complex application so far in the UK and introduction has not been without its difficulties, but the first part has been commissioned and is in use controlling train movements between the new depot building and the main line.

The whole site will eventually comprise 33 sidings and something that TfL dramatically under-describes as a ‘nine road shed’. This is actually a superb train maintenance facility, including five maintenance roads, two high-level maintenance roads, a heavy cleaning road and a wheel lathe road. One of the roads has a synchronised jacking system, supplied by Mechan, which can lift an entire nine-car set simultaneously, eliminating the need to uncouple vehicles.

There is a pair of impressive bogie drops, also supplied by Mechan, with an underground passage leading to the extensive bogie workshop which occupies the side of the building, so that bogies can be brought in and out under the train. The wheel lathe is from Hegenscheidt, complete with a Zephir Kubo tug for train movement. The train washing plant is located some distance from the main depot, by the throat leading to the main line.

Depot operations and safety are controlled from a single desk.

Depot operations and safety are controlled from a single desk.

Safety first

Being brand new, the depot is immaculate, with coloured floors marked out with walking routes and work areas. In various places, a cluster of industrial-looking piping reveals the outputs from the geothermal piles below.

Safety is, of course, a watchword, and the whole of the depot building is under the management of a Zonegreen Depot Personal Protection System (DPPS). Any staff working on a unit must log on to one of the terminals located by each road and, as a further protective measure, attach a personal padlock to the device. The system gives a clear indication of whether any staff are working on a particular unit, essential when they could be at the far end of a nine-car set.

Energisation of that road and train movement is only possible when all personnel have logged out and removed their padlocks. Train status tags are similarly used to indicate equipment that is being worked on or isolated. A less obvious safety measure is a row of small yellow boxes alongside each track outside the building, which are actually derailers in case of unauthorised movement towards an occupied road which may have people working on it.

Building and integrating the new depot with the existing complex railway infrastructure has required considerable teamwork and collaboration with other organisations. As well as the expected detailed interfaces with Network Rail, the site lies alongside the existing First Great Western depot, adjacent to the Heathrow Express depot and the Great Western main line, and just opposite the former Eurostar North Pole depot, now taken over by Hitachi for its Great Western Railway Class 802 trains. And the situation is further complicated by the imminent arrival of HS2 and construction of the new Old Oak Common interchange station.

Assistant project manager for TfL Edward Hamlyn has been involved with the depot construction since the bidding phase in 2012. He explained how the team was determined to complete on time. “Our guiding mantra was that we would not be responsible for holding up the rest of the Crossrail project. We are proud to be ready for the start of services on 20 May.”

Construction of the depot has taken four years, summarised as first access to the site and clearance of existing buildings in 2014, groundworks in 2015, construction of the buildings in 2016 and fitting out in 2017. With the final touches to the depot buildings now being carried out, it only remains for completion of the stabling sidings to see an impressive, environmentally-efficient maintenance facility taking its place as an excellent example for the rest of Britain’s rail network to follow.

This article was written by Graham Coombs.

The immaculate maintenance roads include jacking and bogie drop facilities.

The immaculate maintenance roads include jacking and bogie drop facilities.


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