The first phase of an extensive programme of upgrade works at London Underground’s busy Neasden Depot has reached completion.
Neasden Depot is a London Underground railway depot situated on the Metropolitan Line and is located between Neasden and Wembley Park stations. The depot historically manufactured locomotives and coaching stock, with the final locomotive produced in 1898 and is a very important depot for the continued operation of train travel on the Underground.
Neasden Depot is the largest depot on the London Underground and maintains the Met’s London Underground S Stock fleet. With such a long standing history, the depot has understandably required an update in order to accommodate changes within the industry – step forward the Neasden Depot Upgrade.
The Neasden Depot Upgrade project comprised an extensive programme of works implemented to upgrade and improve services at the North West London facility. Now that the first phase of works is complete, the improved depot is capable of accommodating the new generation ‘S’ stock trains that are currently in use on parts of the London Underground.
Overall improvements to the depot have included the construction of a new train maintenance shed with upgraded lifting equipment, the construction of three overtrack cable crossing bridges and the relocation of a training centre to the northern end of the site. The depot also benefits from improved wheel inspection and repair facilities and additional berthing capacity. During the upgrade operation, the depot’s entire DC traction system received an overhaul and an existing maintenance shed was demolished.
As Neasden Depot is one of the largest and most complex depots in the London Underground network, work on the project was divided into two major phases, with the completed phase encompassing Phase A. The second phase, Phase B, is currently at the design stage and will run through until next year.
Phase A is a £180 million routine maintenance phase, which was split into three major contracts: civil and M&E works; Signal works; and DC traction power. BAM Nuttall was responsible for the civil and M&E works, whilst Thales completed signal works and Balfour Beatty Scott Wilson was appointed the DC traction power contract.
Throughout the civils and M&E contract two lifting roads were constructed, along with an intercar gangway exchange road, a fleet training school and a number of general purpose pitted maintenance roads. Motorised bogey turntables were also installed, a bespoke clean room for circuit board rectification was created and a wheel lathe road was modified to enable the new S stock trains.
The signal works included the installation and commissioning of a new points system, the refurbishment of the pre-existing and operational Train Movement Room, and the decommissioning and removal of the existing signalling assets. During the DC traction power works, two new dc switch rooms were constructed, extensive traction cabling was installed and earthing arrangements were modified and upgraded for the entire depot.
As the original layout of the depot dates back a considerable time, access to the site was incapable of coping with the requirements of a lengthy upgrade operation. In order to combat this problem, a heavy duty tarmac road was constructed to facilitate the transport of construction materials to and from the site.
Another challenge for the scheme was the ongoing predicament of keeping the site fully operational whilst complex engineering works were underway. Neasden Depot remained open throughout the course of the upgrade works on Phase A, therefore night work was carried out in order to keep work on programme.
Phase B of the project is a £60 million phase which concerns the upgrade of heavy maintenance facilities. The second phase is being designed to service a fleet of 191 trainsets and is scheduled for completion in 2015.
Introducing ‘S’ stock
S stock is the latest train stock in the fleet and has been designed to replace existing trains on all sub surface lines. The S stock exists in two types; the S8 which runs on the Metropolitan Line and the S7 which covers the Circle, Hammersmith and City, and District Lines.
The S8 is an eight-car train measuring 133.7m in length, 2.92m in width and 2.88m in height, whilst S7 stock includes seven-cars, measures 117.5m in length, 2.92m in width and 2.88m in height. On both trains every axle is motored, which maximises acceleration rates and improves braking capabilities and doors include obstacle detection and sensitive edges.
Knorr Bremise’s EP2002 system is being used to control the braking on the train stock, whilst traction is provided by IGBT driven AC asynchronous electric motors from a 630V supply. In time, lines will receive power upgrades to 750V, which will allow regenerative braking up to 890V, improving energy efficiency.
What makes the new S stock so interesting is that each train includes the first walk-through gangway on a Tube train. The interior of the train is continuous, which not only improves capacity, but also increases security and will help to improve passenger flow, making Tube travel much easier for commuters. To improve journeys further, the S stock is the only train on the Tube to have saloon air conditioning.
The total seating capacity of the S7 stock is 256, with an additional 24 ‘tip-up’ seats included, along with four wheelchair spaces. Meanwhile, the total standing capacity on S7 stock is 609.
Standing capacity on S8 stock is 697, whilst the seating capacity is 306. As with the S7 stock, four wheelchair spaces are included, whilst ‘tip-up’ seating increases to 36.
The entire S stock employs the tripcock train protection system, which is traditionally used by London Underground, however the system will be upgraded via the installation of the Bombardier Cityflo 659 signalling system. This upgrade will be completed across the stock by 2018.
For more information on the S stock trains, please visit: www.tfl.gov.uk.