Safe and speedy recovery

The terrorist attacks on London’s public transport system on 7 July left many Londoners facing long and indirect journeys to and from work. Tube Lines – the company rebuilding the Tube’s busiest lines – played an instrumental role in getting full services restored in record time. Its Emergency Response Unit and provider of engineering services and equipment Trans Plant worked at all three bomb sites assisting police and moving trains. The Piccadilly line was restored to full service on 4 August – within four weeks of the bombing, just one week after the site was released by the anti-terrorist squad to Tube Lines.

The bomb on the Piccadilly line train was set off on train T311 travelling westbound between King’s Cross and Russell Square, at about 8.50am – within 50 seconds of other bombs at Aldgate and Edgware Road. It did more damage and tragically killed more people simply because it occurred in a single, deep level tunnel. The tunnel was excavated in 1906 and the lining was constructed using bolted cast iron segments. Visual assessments made by our civil engineers on the day of the incident concluded there was no structural damage, but we knew that a bombed train in a single tunnel would be difficult to move. We also knew that Londoners wanted their lives to return to normal as soon as possible, and for us, that meant getting the Piccadilly line up and running.

Operating a full line service could only happen after the conclusion of police investigations and we had no knowledge of how long those investigations were likely to take. In fact, even the police were unsure as to how long they would need. This obviously was beyond our control. What was not beyond our control, however, was restoring a partial service to the Piccadilly line the day after the bomb was detonated and getting the right people with the right skills and tools in place to implement a recovery plan as soon as we were handed control of the site. We worked closely with London Underground throughout the incident to make sure this happened. The co-operation between our two organisations was a significant contributing factor in our success.

Following the Northern line derailment at Camden in 2003, we had reassessed our emergency procedures. It was extraordinary to see how quickly these procedures were implemented and how smoothly they operated; both those run in conjunction with LU and our own internal procedures.

When any kind of incident that affects service occurs on the Underground, an incident control procedure known as Na100 is implemented by London Underground and adhered to by Tube Lines and our counterparts at Metronet. It runs in parallel with the incident control procedures for the emergency services and establishes a chain of command to control the situation and help restore services.

At Tube Lines we established our own incident management team very early on 7 July. By 10am we had an incident room set up in our control centre and later in the morning we created a control room nearer the site at the Russell Square Hotel. By 11am we had a plan in place to enable a limited service to be operated on the Piccadilly line the following day. This meant moving seven trains, which had been stalled in platforms along the line when the Code Amber – an alert to pull all trains into platforms and evacuate – was called. Track operatives worked overnight to provide a shuttle service between Cockfosters and Arnos Grove, Hyde Park Corner and Heathrow and Hyde Park Corner and Uxbridge from the start of traffic on Friday 8 July.

Our objective was clear: we had to be ready to go as soon as the King’s Cross/Russell Square site was handed to us. We had to develop thorough plans, which took into account every possibility, since we could not access the area to confirm levels of damage while the police investigation took place. We developed a comprehensive project plan with more than 300 work activities to be carried out and we had to be able to undertake these activities efficiently, safely and, with inconvenienced passengers in mind, quickly. For this we needed a regimented and disciplined structure.

Our priority was to get the right teams in place to provide 24 hour coverage with all relevant skill sets in each team. Each team consisted of employees from stations, track, fleet, signalling, health and safety, structures and assurance. We ensured these teams were well supported, well rested in lodgings near the site and well fed, so that when we were granted site access we didn’t lose a minute. And we didn’t.

On Tuesday 26 July, when Tube Lines was handed back the site from the police, we made a decision to move the remaining carriages of the incident train that night – the other four carriages had been moved during the police investigation by the Emergency Response Unit and Trans Plant. Until we had done that we could not actually start to repair damage to the assets. The train had not derailed, and while the blast had blown the structure of the train out, the solebar – or the running gear under the floor of the train – was generally OK and the two incident cars were moved by battery locomotive to one of our depots overnight.

A hazard assessment was conducted immediately following the removal of the last two train cabs. The cleaning operation was an extremely important task for us; we had been monitoring asbestos levels, and with temperatures reaching 80 degrees Celsius, the risk of bio-hazard contamination was high. We couldn’t allow our employees to work until that cleaning was complete. Rentokill did a fantastic job cleaning the site, taking account of the fact that Underground assets were not designed to handle the levels of water required for such an intense cleaning operation.

We sealed off cleaned areas to allow assessment teams from civils, track and signalling to start their examinations at the earliest possibility, and the whole cleaning operation was complete by 27 July.

Detailed visual inspections of the tunnel were conducted by our in-house tunnel experts. This work incorporated a 200 metre length of tunnel that could have been affected by the damaged train, with special attention to a 30 metre stretch of tunnel around the site of the explosion, plus inspection of an adjacent crossover tunnel. These confirmed our initial assessment that the tunnel had not been damaged.

While the track was not badly damaged, there was damage to the conductor rail, a set of points, insulator pots that hold up the conductor rail, and sleepers. We had sourced spare points, ceramic insulator pots, sleepers and rail immediately following the incident and had these on the track nearby ready to be moved to the incident site by battery locomotive and track trolleys.

On Wednesday 27 July rails through the entire site were re-keyed, a set of points was refurbished and rubbish and debris was cleared from the area. Ultrasonic testing of the rails took place the following day and all equipment was checked to ensure it was maintained and fully operational.

Insulated block joints were replaced, three switches in the area were overhauled and cleaned, conductor rail was replaced, 10 insulator pots were replaced and six broken S1 chairs were also replaced. A final track inspection on Monday 1 August found the track fit for service.

Repairing the damage to signalling assets was our greatest challenge, and the most time-consuming part of the recovery. We were not given wiring diagrams for the tunnel areas when we took over from London Underground, and we learnt at the Camden derailment site the hugely complex and intricate nature of the signal and power wiring. We were able to apply some valuable lessons on this occasion and had our expert Signals & Electrical (S&E) staff working round the clock to replace broken cable brackets. Once the brackets had been replaced, work began repairing damaged cables, tunnel lighting and tunnel telephone lines. Once all visible damage was repaired all cables through the area were electrically and functionally tested. All signalling between Hyde Park Corner and Arnos Grove was functionally tested to ensure there would be no problems when service resumed.

We had confirmed and received assurance for all our repair and recovery work by Tuesday 2 August. One of our Trans Plant battery locomotives ran the full length of the line in a dynamic testing regime and we were extremely pleased to be able to hand over the line to London Underground for full testing that evening.

Our recovery was fast and effective because we had the right people with the right expertise. We have professional men and women who are used to dealing with incidents, large and small. Whether it’s an incident that happens on the Underground or elsewhere, it has to be controlled, and you have to have confidence in the people doing the job. At Tube Lines I had this from the start. Everybody in our recovery team knew their role; everybody knew what they had to do; and most importantly, everybody was enthusiastic about getting the line up and running. It was the positive attitude of every member of the recovery team that enabled us to recover the site in such a short period of time.

We knew we had the technical expertise to repair the line; what was key in this situation was recovering it safely and quickly. A safe and speedy recovery can only be achieved by people working together as a team and knowing what they have to do. The difficult part is not the repair work – it’s getting to the point where you can use those technical skills in a safe environment.

The announcement that full Piccadilly line services would be restored on 4 August – exactly four weeks after the terrorist attacks – was a proud moment for Tube Lines and an indication of our world class engineering expertise.