CABLES
Clive Woods, programme manager for the Great Eastern OLE renewals project, discusses the vast task of replacing overhead cables with minimum disruption.
T
he 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 em- bargo.
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 opera- tion for such a long time, it could be as- sumed 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 pan- tographs 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
76 | rail technology magazine Feb/Mar 12
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.
© Network Rail
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