No Ordinary Nine to Five

This article is a guest piece contributed by Gavin Silvey, currently Project Manager Capex (Capital Projects) at Tube Lines. Many thanks to Gavin for agreeing to write it, and Tube Lines for the photos.

Deep down underneath London are some of the most challenging logistical problems faced anywhere on the railways today. Space is tight; the tunnels are just about large enough to fit a passenger train through. Storage space is limited too. On the 58km stretch of the Northern line for example, there are only four storage areas. Moving materials in and out of a work site poses major logistical and planning challenges. And then there is the issue of working hours. Unlike the Paris Metro or New York subway, the London Underground doesn’t have a two track system which means that most of the maintenance and upgrade work has to take place at night when there are no passenger trains in service. This gives us anywhere between two-and-a-half to four hours of productive work each night. That is not a lot of hours given we have 255 trains to maintain, 100 stations and 320 km of track to look after. Not to mention 227 escalators, 71 lifts, 2,395 bridges and structures and more than 27,000 signalling assets. So, getting the planning and logistics right is key to getting the actual physical work done properly.

I am currently project managing the points and crossings refurbishment work across our three lines. These are complex rail configurations that can play a disproportionate role in determining service levels. You only have to think about Camden Town and Kennington – two vital sets of points and crossings on the Northern line – to appreciate the passenger impact a fault would have on their journeys. My job is to ensure that by mid 2010, 101 ends of points and crossings are refurbished to bring about improved levels of reliability. Most of these are on the Northern line, which is arguably the most difficult line to manage. The majority of it is buried deep under London in narrow tube tunnels, some of which are nearly 120 years old.

Lifting Rails at Holborn

The first thing we do is survey every point and crossing to better understand the condition of the assets and scope out exactly what work is required. Some sites may only need minor interventions, such as replacing the big metal components – the stocks and switches or the actual crossings. Others might need bigger interventions which require the replacement of all iron work, timbers and ballast or, in the tube sections, the concrete formation. All major renewals require the replacement of the existing bullhead rail configurations with flat bottom rail, which requires an upgrade of points motors from air driven operation to a more powerful modern electric motor-driven set of points. This invariably requires a significant upgrade to the track and signalling assets and also considerable access time so refurbishment is good option as most of the work can be implemented in normal Engineering Hours.

Renewing points and crossings at Edgware

The programme is rolling with small lots of five to ten units being surveyed and scoped at any one time and an implementation programme being devised once scoping has finished. This way the team is able to move from one batch of work to the next without delay.

We also need to take the measurements of all the assets that need replacing, plan resource requirements and order the materials to arrive exactly when we need them. If weekend closures are required on some of the more complex junctions then we must plan for those a minimum of 222 days in advance to give London Underground enough time to plan alternate travel arrangements for passengers.

On any given night we might have about six points and crossing sites being worked on, and this will increase soon to eight sites. For an average site we need to marshal in and out about 20 tonnes of materials. But with so few storage spaces available to us we have had to appoint a logistics supplier of choice which puts all components for each work site on a palette, bubble wrap them and deliver them as and when needed. This gives us much greater confidence in our planning abilities.
As it stands, this major renewals project is going according to plan; of the 101 sites to be renewed by mid 2010 my teams have completed 15 sites with a further 16 with work in progress. Points and crossings at several depots, on the Jubilee line extension, on the Northern line at Kennington and elsewhere, have resulted in much improved reliability for passengers.

There is still plenty to do, however, and pressure on all three lines will soon increase because of the signalling upgrades already in progress. The fixed block systems found on each are being replaced with a Seltrac system which will enable trains to safely run faster and more frequently, enabling a jump in the number of passengers who can travel. This extra tonnage and the higher speeds further increase the imperative to ensure points and crossings are all in good condition.