HomeRail NewsModular S&C goes live

Modular S&C goes live

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The drive to bring about a true seven-day-week railway is forcing Network Rail and its contractors to make changes to the way it works. Ideally, all maintenance and renewals would take place during the short time each night that trains don’t run. That, of course, is impossible. Trains run all day every day – even at night freight trains are crossing the network and passenger trains are being repositioned ready for the start of the next morning’s timetable.

However, night-time is still the quietest time, and the challenge is to do as much work as possible in an eight hour time slot. This might involve the cancellation of the last two trains in an evening and the first in the morning, but the ability to complete most jobs inside eight hours will considerably reduce disruption to passengers.

Working to these restricted timescales demands good planning, thorough preparation and, in some cases, new methods of working. For example, getting onto and off track as quickly as possible extends the working time available.

The introduction of modular systems is one of the initiatives that Network Rail is introducing. Bringing pre-assembled equipment to site that can be easily plugged into the network is an obvious way of saving time. It is being done with signalling, and it is being done on-track with switches and crossing (S&C) installations.

Tilting wagons

The modular S&C programme actually started way back in 2006. Standard designs were formulated which would cover most eventualities and which could be built in factories rather than at the side of the track piecemeal. In 2008, Network Rail ordered 26 tilting wagons from the German company Kirow. It is actually the frames on the beds of the wagons that tilt, allowing them to carry built-up switches at a 60° angle and therefore inside the W6a loading gauge. Once on site, the bed is flattened out and the switch and crossing modular components are removed using a crane.

Delivered during 2009, the new wagons immediately made an impact on the time taken to complete S&C renewals. Capable of carrying a track panel of up to 26.5 metres long, with 3.7 metre bearers, the new wagons were first used in October 2009 at Bamfurlong, Lancashire, where a set of points was replaced in 21 hours rather than the more usual 52 hours. However, there was still a way to go to reach the 8 hour goal.

The answer was to split the 21 hours of work up into segments, none more than eight hours. Network Rail invited Balfour Beatty Rail to participate in a ‘system proving’ programme which had the expressed aim of defining optimised processes and techniques to deliver repeatable sub-eight-hour S&C renewals.

A purpose made facility was set up on sidings at Beeston near Nottingham. The two companies then carried out detailed trials of all known existing and new techniques and equipment to develop a definitive ‘eight hour’ method. All S&C supplier delivery depots undertook training, planning and trial sessions at Beeston to rehearse and prepare for eight hour S&C renewals.

However, to implement what had been learned at the Beeston practice facility on the live main line required both a change in mind-set and detailed preparation. From January 2012, Balfour Beatty Rail’s Eastleigh Depot, part of the Western Integrated Management Team (IMT) delivering track renewals on behalf of Network Rail on the Wessex area, took part in several workshops to ensure that they would be ready to deliver modular S&C. It was nearly time to use these new techniques on a real job.

Preparing to go live

All that was needed now was a site and a midweek possession. Two suitable sites were selected on the main line from Waterloo to Weymouth, at Wool and Wareham on the Dorset coast. In this area, two new crossovers were to be installed as part of a resignalling scheme – they would need to be cut into the existing plain line.

Wool would be the first one tackled and the Eastleigh construction team began planning for the important day. Project manager Tony Stephens, assisted by site manager Mike Fry and lead technician Martyn Cattermole, worked everything out to the last detail.

As the renewal drew closer, telephone conferences were held to ensure that everything would be in place and ready for the first shift. This included such elements as checking wagon orientation with the freight hauliers and making sure that road-rail vehicles (RRVs) and other plant would be available on site with all pre-checks completed.

Dress rehearsal

Even taking possession of the track following the last train was planned to reduce the time needed as far as possible. Network Rail’s local NDS team pulled out all the stops with a preparation week to rehearse and fine tune any issues that might arise. They achieved and delivered a time of 16 minutes from the last train passing the possession limits to detonator protection being in place to allow work to start.

With the help of Balfour Beatty Rail’s on site team, the 750V DC third rail also had to be de-energised and earthing straps fitted to protect the site from any stray current. This was reduced to a further five minutes through good communications and site familiarisation.

By cancelling some late-evening trains, a possession time of 8 hours 15 minutes was available, with a buffer of an extra hour if needed – after all, this was the first time this had been done on a live railway.

In the days leading up to the main possession, as much preparatory work as possible was carried out. The plain line that would be removed was cut into 30-foot lengths in readiness and then plated. The third rail was similarly cut and prepared to mirror its final position. A tamper went through the site to make sure that both alignments were to specification so no major tamping work out side of the renewal limits would be needed on the night. A temporary roadway was laid in the adjacent fields and access points for RRVs created from extra ballast to ensure quick egress and entry into the site. All rail drilling was completed prior to the core work.

Just in case, a mitigation plan was drawn up, ensuring that every conceivable ‘what if ’ scenario was accounted for. While the team was confident it could perform, it had to be prepared if things went wrong.

Here we go…

On Monday 24 September the planning was complete, and the challenge commenced. At 9pm, the possession was taken quickly and the conductor rail was removed. RRVs removed the pre-cut track panels from the Down line and the tilting wagon, accompanied by Balfour Beatty Rail’s 1200 tonne Kirow rail crane, came on site – right on time. The tilting wagons were flattened so that the crane could be ready to take the first part of the new modular units off the wagon. By using a special lifting beam, the segments were kept horizontal with no deflection in the middle.

The old ballast was removed using excavators and new ballast was levelled out by a laser-controlled bulldozer with 3D instrumentation. The first panel of the new crossing was installed less than three hours after the start of the possession. This first half of the modular crossover came in five parts, with the points motor already fitted, and these were lifted off the wagons one after the other and installed to a tolerance of ± 20mm. The fifth and final panel was in place after just over four and a half hours.

Now it was a case of removing the crane and the tilting wagons, with their beds tilted back to the running position, and finishing off the installation. The conductor rail and electric cables were reconnected, ballast was added and the tamper passed through the site achieving a track hand back tolerance that was fit for 50mph, although it would be reopened with a temporary speed restriction of 20mph while work continued.

Once signalling installation and testing of the points and track circuits was completed, the new switch was padlocked so it would only work for straight line running. The whole possession was handed back at about 05:20 – the job had taken just a little over eight hours and the railway was back in operation.

On Tuesday night, the plated joints were welded up, the tamper went through again to consolidate the ballast and achieve the final design, and more top stone was unloaded.

Repeat performance

Wednesday night was a repeat of Monday, although in reverse with work taking place on the Up line and all the tilting wagons on the Down. The team was a little quicker this time; taking about 12 minutes over eight hours to install the second switch and crossing units and connecting it to the first one using bearer tie plates, completing the installation

On Thursday night the tamper was again deployed, the final joints were welded, and the line speed increased to 50mph on both lines. The following week, stressing of the track would restore the full line speed of 80mph without any need for further tamping.

So four night-time possessions, none of them more than 8 hours 20 minutes long, had seen the installation of a brand new crossover.

In October, at Wareham, Balfour Beatty Rail’s Eastleigh team did it again, proving that night-time S&C installation is now almost routine. Steve Everest, programme manager for modular S&C at Balfour Beatty Rail, sees no reason why a crossing replacement should take any longer “providing the teams prepare well and each team member fully understands the plan to the very finest of detail.”

The whole modular S&C overnight concept will now be rolled out nationwide and Balfour Beatty Rail’s next one will be at Tottenham Hale, although this time the Ipswich-based team will get to do it. Similarly, the other Network Rail contractors will get their chance – they were all invited to witness the works at Wool and Wareham to share best practice.

So did everything go as planned? Almost.

Steve Everest commented, “Like all new concepts we had our issues, each being different on all four nights of the installation. But by learning from these and ensuring we work at reducing the down time we could have saved a little more time, and definitely got well under the eight hour target. When signalling points and track circuits are also tested under the ‘plug and play’ concept, further time reductions will also be possible.”

These first installations, pioneered by Balfour Beatty Rail’s Eastleigh team, have set the benchmark for modular

S&C installations, proving what is possible and taking one more step towards making the seven day railway a reality. Network Rail, the ultimate customer, is very pleased. “The work at Wool was a perfect illustration of the impact we want modular switches and crossings to have on the railway,” enthused Steve Featherstone, Network Rail’s programme director for track and infrastructure.

“As a company we have to listen to our customers, and what they are saying is that they want us to work on the track at times when passengers don’t want to travel.

“Of course, we cannot always achieve that aim, but the flexibility the modular switches gives us means we can achieve so much more with overnight midweek work that we don’t have to close the railway so often at weekends.”

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