Know When To Run: The Story Behind The Xmas Kings Cross Problems ! 11:50, 24 January 2015 " John Bull (http://www.londonreconnections.com/author/admin/) — 244 Comments # (http://www.londonreconnections.com/2015/know-run-story-behind-xmas-kings-cross-problems/#comments) Delays and work overruns aren’t an uncommon part of the Christmas experience on London’s railways. Ultimately, maintenance and improvement needs to be carried out and from a utilitarian perspective the opportunity to do so in a period where passenger numbers are generally lower is simply too good to miss. It is rare, however, to see quite the level of disruption and overcrowding that was witnessed at Finsbury Park and on the East Coast Main Line last Christmas as a result of overrunning works between there and Kings Cross. Indeed, whilst it was not quite the disaster that the media and some politicians seemed determine to make it, it was certainly extreme enough to warrant further investigation, and a full report into what happened was swiftly commissioned by Network Rail. That report is now out (http://cdn.londonreconnections.com/2013/kingscrossdisruption.pdf), and it makes interesting reading. For it provides a window into the events that happened that weekend. Some serious works This particular Christmas period was a busy one for railway work. With Christmas falling on a Thursday, Network Rail were presented with what they saw as a rare four day period in which to carry out engineering work. Closures for the entire period would, of course, need to be avoided wherever possible, but it was still an opportunity. Part of the East Coast Main Line, the section of the railway known as “Holloway Junction” (or just “Holloway”) is approximately 1½ miles and lies north of King’s Cross Station. Network Rail planned to take advantage of the festive period to replace two of the junctions there and 500m of the two railway lines between them. The work itself wasn’t unusual, but the scope was relatively ambitious. Ultimately over 6,000 tonnes of ballast would be replaced along with the rails and sleepers which sat on them and it was thus a considerable engineering and logistical challenge. (http://cdn.londonreconnections.com/2013/hollowayjunctions.jpg) The two junctions and stretch of track to be replaced In truth, all four tracks at Holloway needed renewal works, and a full seven day blockage had been considered to allow exactly that, but in the end it was difficult to justify the amount of disruption this would cause. Instead it was decided to carry out the work in two four day blockades, one at Christmas 2014 and one a year later at Christmas 2015. Both would focus on two sets of tracks each. Although work was focused on only two of the tracks, for logistical reasons Network Rail would actually have to take possession of all four lines at Holloway for the bulk of the work’s duration. This was partly due to the scale of the work, but also because works being undertaken elsewhere along the East Coast Main Line meant it would be impossible to bring the necessary engineering trains straight from their depots. Instead, all fourteen engineering trains required at Holloway had to be brought up before work began and parked up. (http://cdn.londonreconnections.com/2013/freighttrain.jpg) A typical engineering train, photo credit: Mike Rowland, Taunton Trains (www.tauntontrains.co.uk ). The end result was a worksite that was of considerable size, stretching over all four lines, running to almost nine miles in length and requiring more than a little choreography in both work plans and train movement. That work site would, however, have to shrink on the 27th December. This was because the main junction at Watford on the West Coast Main Line was also being renewed at the same time, leaving two of the key north/south routes closed at the same time. In discussion with the Train Operating Companies (TOCs) Network Rail thus agreed to hand back two of the tracks at Holloway in time for trains to at least operate a reduced timetable on the 27th. In effect, Network Rail would have two days of their blockade with all four lines at their disposal, then two days with only two of them, and the work programme was configured around this. This all meant a number of tasks having to be carried out in serial not parallel, but the likelihood of success was calculated to be 95%. A success rate of 95% met Network Rail’s minimum requirements, but in order to help achieve this it was decided to take extra steps to assure the risk of equipment failure was minimal. This was crucial because if something failed there would be limited ability to bring in replacement equipment due to all the work going on elsewhere. Critical to the work were the Road Rail Vehicles (RRVs) that would be used and the log grabs they would be equipped with. Seven log grabs were required for the work and the plant supplier agreed to supply Network Rail with eight brand new ones, the intention being to minimise the risk of failure and to ensure that there was a spare on site. They also agreed to provide an on site fitter so that any problems could be dealt with quickly. (http://cdn.londonreconnections.com/2013/rrvs.jpg) Typical RRVs (http://cdn.londonreconnections.com/2013/loggrabbers.jpg) Log grabs The work – and the problems – begin On paper everything seemed in order, but when work began on Christmas Day, things began to go wrong from the beginning. An hour was lost waiting for the OHLE to be isolated and permits confirming such to be issued. This was due to the sheer number of projects on the route, all of which had been planned to start at the same time. Despite Holloway being second on the priority list, it still got delayed. Then “scrapping out” – the process of cutting, dismantling and moving the 500m of old track to be replaced took three hours longer than planned. In part, this was due to the scale of the work involved. Although sufficient operators were on site for all the machines, the number required meant that not all of them had much experience of this particular type of work and it took them longer than anticipated to carry it out. This wasn’t, however, the major problem. That was the plant equipment – most particularly the log grabs and RRVs brought in to operate them. The fact that these represented a potential critical risk to the success of the possession was something that Network Rail had obviously anticipated – this was why brand new log grabs had been sourced for the work. What nobody had realised, however, was that by doing this they weren’t lowering the risk of problems occuring, they were simply trading one risk for another. That second risk reared it’s ugly head almost immediately. The new log grabs had never been used on these particular, or indeed any, RRVs before and it soon became apparent that – for reasons as yet unclear – the fittings didn’t fully match. Throughout the rest of the work, the fittings between the RRVs and log grabs spewed hydraulic fluid at a prodigious rate, losing pressure and failing to work. The on-site fitter worked hard to try and solve the problem but ultimately a specialist had to be called in from off-site. Scrapping out finally finished at 09:00 on Christmas Day. By then all of the above had conspired to eat through any contingency time already allowed for this stretch of work and beyond. The project was now running three hours behind. The first decision point It was now decision time for the project team. With scrapping out complete the next step in the work was to excavate out and replace the ballast and here they had two options. The first was to stick to the original plan, despite the fact that the project was already running late, and excavate out as much of the ballast as possible (down to a depth of about 30cm). Alternatively, they could go with the quicker option of simply “skimming” the ballast. Ultimately the difference between the two options was one of quality. The deeper the excavation, the longer the new junctions and track would last – potentially up to 25 years. Skimming would be quicker, but it would drastically shorten that lifespan, meaning the work would have to be repeated in perhaps just ten years. This was, in effect, the point of no return for the project team. Once full excavation had begun they would not be able to switch to skimming later on if it became apparent they had made the wrong call. This is because doing so would leave the resulting track on an inconsistent foundation, increasing the risk of future issues or even a derailment. Stick to the original plan and risk overrun or compromise on the work? In the end the decision was made to proceed. This was not just to avoid doing future work. It was also because the team knew that the plan actually allowed for up to four hours delay in completing the excavation stage of the work. This meant that, assuming nothing else went wrong, they could absorb the three hours of delay they had already inherited from the scrapping out phase in that. Indeed they were even hopeful of making some of that time up. Given that technically they were not yet officially over time they also decided not to officially declare an overrun at this point.