Interviews

The restrictions of renewals

Clive Woods, programme manager for the Great Eastern OLE renewals project, discusses the vast task of replacing overhead cables with minimum disruption.

The Great Eastern overhead line renewals project involves the replacement of cable equipment that has been in operation since the 1930s. Starting in 2007, this complex programme of works has run from Liverpool Street to Shenfield, and will continue to Chelmsford by the time it is completed in December 2014.

Programme manager Clive Woods spoke to RTM about this comprehensive project, the new and innovative working practices involved, and managing the Olympics embargo.

Ageing equipment

He said: “This is very old equipment which is very heavy to work on. Clearly we have some reliability issues. The project is replacing everything along there; most of the structures and all of the overhead lines are being replaced with a Swiss system. It has auto-tension to remove the need for speed restrictions in hot weather.

“At the moment we’ve replaced all the lines that we were remitted to, up to the London side of Stratford station: all of that is complete. We’ve also completed a couple of miles on the country side of Stratford station – some of that is now complete and were just starting work around the Ingatestone area.”

Considering the cables have been in operation for such a long time, it could be assumed that technological advances would lead to significant differences in the system. But Woods said: “It’s still the same sort of system that’s been up there since the early days, which is quite surprising when you think about how long it’s been there.”

There is some wear, dependent on the pantographs that are being used, but these are inspected on a very regular basis to ensure that any in poor condition are identified and replaced.

Concentrated construction

The project is costing in excess of £200m, with the greatest bulk of work conducted in blockades during Christmas and Easter. Since there is such a small possession window for the work to take place in, this involves deploying around 200-300 people each time – making good management essential.

To make the most of the limited time available to the team, negotiations with the operator have allowed this period of work to be extended to include midweek nights, from Monday to Wednesday. Staff can then put in foundations and structures alongside the track and conduct trial holds and inspections.

Woods said: “Previously on possessions during the night time we’d only get about half an hour to an hour’s working time, which is not very effective. So we agreed with the operator extended times in the evenings. That’s giving us about four to four and a half hours on the track. We’re delivering huge amounts of work during that time, which is significantly reducing the length of time that we’re going to have to work later on.”

Network Rail has also just begun work with the OCR (Overhead Condition Renewals) team, using wiring trains to speed up the process of renewal. These replace the manual practice of de-wiring and re-wiring from baskets on elevated work platforms with a method that is “almost automatic”. The trains have pre-loaded wire on drums, and the team can then work off platforms built onto the train, wiring onto the machine itself.

“That’s some fairly major new technology that we’re deploying. Previously the length of track that we’ve been wiring would have taken in excess of two years. We’re anticipating being able to do that in basically under a year. That will make a significant reduction in the time the project takes,” Woods commented.

The Olympic embargo

The maintenance organisation has been running inspections leading up to the Olympics; ensuring faults are rectified prior to this event. The cable renewal project will be halted during the Games, resuming in the autumn when both the Olympics and Paralympics are out of the way.

Woods explained: “If you go into an area and try to upgrade it or modify it, you’ve got a risk that the modifications have a chance of failure. If you’ve made a mistake, which we hope we won’t, it’s not worth the risk.

“Leading up to the Olympics there’s a lot of maintenance work being undertaken. “We’re going to fix a number of areas that needs rectifying.”

The pause for the Olympics has been part of the plan from the start of the work, allowing the event to be incorporated into the programme. At this point, the project will stand down and go into ‘support mode’, working with the maintenance organisation.

“If there are any issues arising, Network Rail as a company will be able to respond to it, regardless of which parts are involved. We’re doing that to make sure that any response is as fast as it could possibly be,” Woods said.

This break in the programme will not affect reliability during the Olympics, as the main thrust of the work, from Liverpool Street to Stratford, will already be complete. This means that the greatest number of passengers will benefit from the new cables along the majority of the Great Eastern line.

Limiting disruption

Such a large project will no doubt run into a few challenges, and these include the level of disruption that necessarily accompanies the re-wiring and structural work, as well as managing the logistics of a large workforce in tight time periods.

Woods said: “What we’re doing is extremely disruptive. With some exceptions, we can’t work with trains running nearby to where we’re working. We can put some of the civil structures in – foundations, parts of some of the big steel structures – but that’s about as far as we can go without shutting down the railway.

“On the whole, we have to do this by taking out all four tracks at a time. There are some areas where we can take two at a time, depending on how close various parts are, but we have to isolate. We turn off the power. All the trains, especially passenger trains, are electric, so it means that services can’t run and we recognise that that’s extremely disruptive, especially over the weekend.

“Unfortunately, there’s no other way we can get in there to wire, because we do have to switch the power off to change the wires. These things are running at 25,000 volts, so it’s got to be off. That’s a big issue.”

This is one reason why the wires have been in place for so long without any upgrades, as the level of disruption is just too high to manage regular renewals effectively.

Woods explained that they had investigated alternative options, but working on weekends and during holidays turned out  to be the best approach.

He continued: “One option, theoretically, could be to block the whole of the Great Eastern route and do it in all one big go. We did actually explore how feasible that would be, but the amount of disruption to the passengers is just unimaginable.

“If you consider blocking something like the Great Eastern for four months, it’s just huge. People have got to get into work and services have got to get in, so we’ve taken the conscious decision to go in at the weekends, get extended midweek nights wherever possible to get the most done that we can and try to minimise disruption to the travelling public. That’s one of the biggest challenges.”

Commenting on the practical difficulties involved with managing this project, Woods added: “Of course you have the logistics within that of bringing 200-300 people plus all the machines, into the possessions where we’ll be working over a weekend, or over ten days over Christmas.

“It’s a huge logistical operation to get this done.” 

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