Dynamism doubles Lugton's loop
24 Feb 2010
Since 2006, Transport Scotland has had responsibility for most rail powers in Scotland and it has certainly not been idle. We hear a lot about the renaissance of railways and this is particularly apparent north of the border with passenger numbers up 24% since the start of the current ScotRail franchise in October 2004. Punctuality too has improved by an impressive 50%.
Transport Scotland is being progressive both in the reinstatement of closed lines and upgrades to existing routes and infrastructure as witnessed by the high-profile Airdrie-Bathgate and Stirling-Alloa-Kincardine scheme. A more modest route enhancement that's widely regarded as long overdue has been recently completed, allowing a doubling of services between Kilmarnock and Glasgow.
The line between Kilmarnock and Barrhead was singled in the Seventies when the Down (northbound) line was removed. Just one intermediate passing loop at Lugton was provided, with the single line sections on each side being worked by Scottish Region Tokenless Block. The resulting restriction on train services has been the subject of public campaign and parliamentary debate ever since. Three intermediate stations, Kilmaurs (opened in 1984), Stewarton and Dunlop had inadequate facilities - bus stop type shelters and just an hourly train in each direction. But it could have been worse - incredible as it might now seem, complete closure of the line was approved in the 1960s. Thankfully, a vigorous anti-closure campaign saved it.
Making plans
The idea of a dynamic loop - allowing two trains to pass without stopping - was first mooted in 1986. There was no business case for doubling the entire line but the dynamic loop would allow the train frequency to be doubled, facilitating a half-hourly service. Replying to a written Parliamentary question in May 2006, Minister of Transport Tavish Scott said "Strathclyde Partnership for Transport has commissioned Network Rail to look at provision of a new dynamic loop between Stewarton and Dunlop with the option for this to be extended to Lugton. Transport Scotland is working with SPT and Network Rail on progressing this scheme as quickly as possible."
Progressed it was, and although SPT pulled out after the initial feasibility study, Transport Scotland went on to provide the funding. The scheme would involve the reinstatement of the former Down line over a distance of 9,360 yards or 51⁄ 3 miles.
Starting from a point just south of Stewarton Station, the new track would meet the existing Up/Down Loop at Lugton, made easier by the MoD having declared the Giffen branch surplus to requirements. This freight-only route had made use of the former Down line at Lugton to run parallel with the Up/Down Main over a distance of about 20 chains. In addition to the new track, the existing single line would need to be partly relaid and slewed to form the Up Main. In all, the work would involve the installation of over 7,000 yards of new rail, steel sleepers and ballast, 6,000 yards of drainage and 11,000 yards of lineside troughing.
Funding
Brian Sydney, the Network Rail Project Sponsor, explains the funding in more detail. "The scheme is essentially financed by Network Rail by adding it to the Regulatory Asset Base (RAB) after reaching agreement with the ORR. The £27.5 million cost is initially provided by Network Rail and this is paid back by the Scottish Government over an agreed time period. We also took the opportunity to include scheduled renewals under the Network Rail CP4 determination, adding a further £1 million to the overall cost." The train operator, ScotRail, was not involved in the funding.
Installation
Planning and development began in 2007, with work on the formation starting in September 2008 and station improvements in early 2009. Jarvis was the main contractor and their designer was Atkins. Some of the station improvement works were undertaken by Pennant Civil Engineering, part of the Harte group of companies.
As well as the provision of new platforms on the Down side at Stewarton and Dunlop, the existing platforms on the Up side were rebuilt and extended to accommodate six-car trains. The one platform at Kilmaurs Station on the southerly single line section was similarly upgraded. An interesting development at Stewarton saw the reinstatement of the original platform underpass, filled-in when the line was singled. It was unearthed, found to be in excellent condition and has been restored to a better than new state. Access ramps for those with restricted mobility have also been provided, together with CCTV, PA, help points and ticket vending machines at each station.
Keen to explain the scope of the works is Network Rail Project Manager Eleanor Day. "As well as the track installation work and station improvements, the scheme involved the demolition of two redundant overbridges, the replacement of two bridge decks and strengthening work at Annick Water Viaduct at Stewarton."
The new decks were installed at bridges 85 and 88, either side of Stewarton Station. The latter gained notoriety when, on 27th January 2009, the original deck collapsed under 6B01, the 0520 from Mossend to Riccarton Oil Terminal near Kilmarnock. The train, comprising ten 100-tonne oil tanks, was loaded with oil, diesel and kerosene. The rear six tanks were spectacularly derailed and a serious fire broke out. Fortunately no one was injured. Track doubling works - already in progress at this time - were seriously disrupted. The line itself was closed for three weeks.
"Spandrel wall tie-bars were installed at Stewarton (Annick Water) Viaduct and remedial stitching work undertaken" continues Eleanor Day. "We also added tensioned wire rope handrails. Because this structure is a listed building, Network Rail was required to liaise with Historic Scotland before any of the work could commence. At seven overbridge sites, the track has been lowered to provide a W9 loading gauge on this route." The line was previously engineered to W6 gauge. The other viaduct involved in the scheme, Glazert Viaduct just south of Dunlop Station, required no attention.
Once the new Down Main was in position, it was connected by temporary slews to allow the former single line to be slewed and partly relaid. Finally, at the southern end of the loop, a pre-assembled high-speed turnout was installed using PEM/LEMs.
Signalling
Jarvis undertook all of the signalling design work and implemented it. Lugton signal box controls the entire dynamic loop; both lines are bi-directionally signalled using Dorman LED-type signal heads and conventional DC track circuits. LU2, an additional stop signal, is provided on the loop in the Down direction in advance of Stewarton Station. It is approach-lit so as not to display a red light to the driver of a Down train using the Up Main. The signal in rear, LU7, is three-aspect whilst all the other colour lights are two-aspect. The single line sections to Kilmarnock and Barrhead remain under Tokenless Block regulations but this system has been transferred onto the Fixed Telecommunications Network (FTN) fibre optic cable. Tail lamp CCTV cameras are provided at the exits from both single line sections.
At the south end of the loop, now named Lochridge Junction, an IAD Rail Systems HPSS point actuation system has been installed. Brian Sydney explains that "We take into account whole-life costs and that, together with the need for a 70mph turnout, dictated the use of the HPSS S&C unit. At Lugton, the financial case for replacing existing pointwork and semaphore signalling didn't stack up so these remain largely unaltered, but a replacement block shelf and new interlocking was installed."
At the north end of the Lugton layout, 27 Points were converted from 30 Volt to 110 Volt operation. All of the new signalling is controlled from the existing lever frame at Lugton although the new interlocking, together with a new 650V signalling power supply, is housed in an adjacent REB. AWS and TPWS are provided.
Performance benefits
Following a freight or stopping passenger train, the headway provided by the dynamic loop, its associated signalling and a 70mph linespeed is 9½ minutes in the Up direction and ten minutes on the Down. This reduces to seven and eight minutes respectively behind a non-stopping passenger train. With the introduction of the new timetable on 13th December, ScotRail began running the long-awaited half-hourly service of 34 trains in each direction every weekday. Almost 85% of these call at all stations. The Sunday service is largely hourly. Class 156 Super Sprinters presently form all services and ScotRail currently has no plans to replace them. "We are delighted with the response to the new services" added a ScotRail spokesman. "It's great news that even more people have the opportunity to switch to public transport and are choosing rail as their preferred mode of travel."
Eleanor Day sums up her feelings about the project. "I'm delighted that the key achievements of this scheme have been met with no RIDDOR reportable accidents. All the key milestones were met and the project was delivered on time and within budget. The working relationship between Network Rail and its contractor, Jarvis, made all the difference. Projects like this always throw up a lot of challenges and this was no exception, but it's so much easier to meet those challenges when all those involved have a ‘can do, will do' attitude and work together to meet the end goal. Most importantly, the ScotRail passengers in Ayrshire are now enjoying the benefits of this long-awaited investment."
Ron McAulay, Network Rail's director Scotland, said "This new Glasgow-Kilmarnock half-hourly service is designed to promote economic growth and optimise economic benefits whilst meeting local needs and expectations. It also supports the medium to long-term objectives in Scotland's railways of enhancing the services throughout south-west Scotland and beyond."