New Cross lies on a route of critical importance, on the line between Kent and London Bridge, very close to the throat of the latter. It is one of the most heavily used commuter routes in the UK, and very sensitive politically. With London rail issues already in the news before Christmas, Network Rail could not afford work in this area to go wrong during the 2016 Christmas engineering campaign.
Rail Engineer heard from Network Rail’s Cameron Downey that the 98- hour blockade at New Cross had come dangerously close to over-running, but was eventually delivered on time thanks to good planning, contingency measures and experienced and cool thinking people.
Switch diamonds
The job commenced at 00:01 on Christmas Eve, with the objective of renewing eight S&C units, which comprise two three-line crossovers, and handing the railway back into use at 04:00 on Wednesday 28 December.
The renewal was complicated as it involved two sets of switch diamonds in addition to normal switches and crossings. Switch diamonds are complex and notoriously difficult to set up, commission and test satisfactorily. Furthermore, besides the S&C, the project team was charged with renewing some 800 metres of conductor rail, replacing two sets of hook switches with modern isolation systems, installing and commissioning point heating on the new S&C and, last and far from least, installing and commissioning the required signalling systems.
Cameron works in the S&C division of Network Rail’s Infrastructure Projects (IP) Track organisation, and his responsibilities are not restricted to just this one project. The team he works in is responsible for a rolling programme of renewals and undertakes enhancement works too. It is, for example, involved in work at Euston for HS2 and in Wessex.
The New Cross works were undertaken under an alliance contract within which Network Rail, Colas Rail and AECOM staff all work in one team, with getting the job done safely, on time and to budget the key goal for everyone. There is a totally collaborative culture – it matters not which company an individual works for.
The team faced two particular challenges in planning and executing the New Cross works, imposed by the timing and location of the job.
Timing was important because the works had to be done during the Christmas period, when many other significant works were also to take place across the rail network. This meant that specialist equipment, such as tilting wagons for S&C delivery, were in exceptionally high demand.
For all its importance, New Cross was never going to have sufficient priority to guarantee the availability of such kit, and from the outset the plans for the job had to be made assuming that other alternatives would need to be employed.
Constrained site
The S&C site is on the top of an embankment, and is hemmed in by railway and other infrastructure. There is very little room on the site to store plant or materials and, because of other works, any engineering trains were going to have to enter and leave the site from the same end, the country end.
Fortunately there is a small area of land at the bottom of the embankment where prefabricated S&C panels could be stored. An access road from there to the lineside was practicable, though somewhat convoluted and tricky.
A plan was therefore drawn up for the job, involving a Kirow crane to make the final placements of the S&C panels at track level. That was straightforward and conventional. However, feeding the panels to where the crane could reach them to pick them up for placement was another matter.
As already mentioned, the 40 odd S&C panels were delivered to a stockpile area at the base of the bank. They were brought there from the S&C manufacturer, VC UK of Scunthorpe, in small numbers by lorry over a period of several weeks beforehand.
The awkward roadway from the stockpile to the small lineside area from which the Kirow would take the panels for installation meant the use of two large tracked machines lifting each panel and carrying it in tandem. This activity became critical to the timing of the whole works, since it was important that the Kirow crane was kept supplied with panels continually if time was not to be lost.
To further complicate matters for Cameron and his colleagues, his team was also responsible for another significant site which was proceeding in parallel, Queenstown Road on the Wessex route. This was also an S&C installation, meaning that similar skills were needed on each site.
The result was that, in the full spirit of collaboration, people who are normally office-based came to work out on site on one or other of these jobs, to ensure that both were provided with sufficient human resources.
The wider area
Whilst the New Cross works went on, there were adjacent lines which remained open to traffic. There were also many other works going on around New Cross – on Thameslink, at Lewisham and more. Bridge, track maintenance and electrical works were amongst these nearby activities, affecting engineering train access and other aspects of the New Cross job.
The S&C installation of this roughly £4 million scheme proceeded very much to plan, despite all of the complications, and everything was looking rosy on the Monday when the installation was completed and first tested. Then the gremlins struck!
On the Tuesday, when formal ‘wheels free’ testing commenced, one of the two switch diamonds misbehaved. It proved impossible to get it correctly set up and performing to specification, and the cause of this was not readily apparent.
It was at this point that the value of contingency planning and resourcing became obvious. The project had sufficient resources and expertise available to effectively dismantle the switch diamond concerned and rebuild it on site.
Various possible causes for the fault were identified by the experts involved, examined, and then eliminated without curing the problem. In the end, it came down to a microswitch installation, but it turned out that the microswitch itself was not at fault, it was the metal case it sat in that was defective!
Seemingly, nobody concerned suspected a simple, fixed metal case like this could have had anything to do with the fault, but after eliminating everything else that they could think of, they tried replacing the case, and the problem disappeared!
The solution was found, after a lot of hard work, just in time to complete the testing and commissioning and hand the tracks back into traffic by the planned time – a great team effort.
Written by Chris Parker
