Written by Collin Carr.
Progress with the redoubling of the 86-mile Cotswold Line has featured in previous issues of the rail engineer with David Northey, Network Rail’s Commercial Scheme Sponsor, outlining his company’s plans and aspirations for the 45-mile section between Charlbury and Worcester.
Now David Quintin, programme manager for Amey, reveals how the work is progressing and looks forward to the start of the final phase.
The line’s current operational problems stem from the controversial regional routes survival strategy that emerged in the 1960s when track and associated infrastructure were removed to leave a single track with occasional passing loops.
This approach was adopted for the Cotswold Line and many others, and it had a significant impact on the frequency and reliability of the train services provided.
Of course, this was balanced by a significant reduction both in day-to-day maintenance expenditure and capital costs for ongoing track and infrastructure renewals.
Today, these savings do not outweigh the potential benefits of an improved service on this route.
As a consequence, the Office of Rail Regulation gave approval in 2008 for the reinstatement of a total of 21 miles of double track between Charlbury and Ascott-under-Wychwood (20%), Moreton-in-Marsh and Evesham including Chipping Camden Tunnel (75%) and Evesham toward Pershore (5%).
Signalling and commissioning
Approval was also granted for the modernisation of the route’s signalling system and the relocation of all controls to the recently constructed state-of-the-art Thames Valley Signalling Centre at Didcot.
However this aspect of the scheme has subsequently been re-evaluated and a decision made to only renew signalling components where necessary, rather than the whole route’s system. Local signal boxes will therefore be retained.
Other associated work includes the construction of new platforms, earthworks, bridges and drainage systems, as well as level crossing improvements and refurbishment.
In total Network Rail is investing more than £67 million upgrading the Cotswold Line and the scheme is now nearing completion.
There will be an increase in train capacity, offering an hourly service to London, increasing to half-hourly during peak times, together with much improved reliability, increasing from the current rate of 76% to an anticipated 92%.
Network Rail appointed Amey as main contractor for a significant proportion of the scheme. Included is a wide portfolio of Amey’s capabilities – signalling, telecommunications and electrical work, delivery of new platforms and a full design service.
Track installation has been carried out by Amey’s joint venture with Colas.
David Quintin detailed what has been completed so far and what’s still left to do, leading up to two critical commissioning dates. The first came on 28th May with the start of a nine-day blockade whilst the second, hot on its heels, is 6th August when a 16-day blockade gets underway.
Making way
By January 2011, Network Rail and AmeyColas had already realigned nearly 14 miles of single line sections between Moreton-in-Marsh and Evesham, additionally preparing new formation for the proposed second line.
This included track within the 157-year-old Chipping Camden Tunnel, designed by Brunel, which is 811m long and runs between Mickleton and Blockley. The existing track has been realigned and a second one already installed. This work was carried out using a new unique self-propelled track construction train.
To accommodate the two tracks, the current formation had to be lowered and more than 12,000 tonnes of ballast material removed from the tunnel for recycling.
A drain was buried beneath the six-foot and is now linked to more than 2000m of drainage that has been installed outside the tunnel to prevent flooding.
David Quintin explained that to facilitate the process of moving the track into its final alignment, much of the signalling equipment along the route had to be moved temporarily.
Carried out by Amey, this specialist work included the relocation, construction and installation of 60 sets of control equipment cabinets, seven colour light signals, 21 miles of new surface concrete cable route and 30 miles of cable.
The temporary positions for the signals had to be fully assessed, with vegetation cleared to provide the correct sighting. This will continue throughout the work to ensure that the plant life does not return insidiously and restrict signal visibility.
Cutting back the foliage has also helped make room for the relocated equipment and troughing.
Late last year saw another key milestone – the installation of a new underbridge deck at Honeybourne. This is a post-tensioned reinforced concrete span, designed to carry two tracks. Once on site, it was assembled on trestles and tied together using Macalloy bars.
A 600-tonne capacity ten-axle modular transport unit was used by Birse Rail, Network Rail’s contractor for this job, to remove the old deck and then carry the new one into its final position.
Ticking clock
So that’s the work that has been completed so far and all is ready for the next phase – the redoubling of a five-mile stretch of line between Ascott-under-Wychwood and Charlbury, due to be commissioned during the nine-day blockade that started on 28th May.
At the time of writing, the signal box at Ascott is in the process of being upgraded from mechanical to an NX panel. This is to accommodate relay-based signalling typical of the old Western region. A new platform is under construction at Charlbury, as well as a new DDA-compliant footbridge.
The station there is Grade II listed so considerable attention to detail is demanded. For example, Cotswold colour stone blocks are being used for the platform walls and all paint for the work has to be compliant with heritage colours.
A special planting area has been included on the new platform which the local horticultural college will maintain – just one of many initiatives designed to involve the local community in the project.
An interesting aside, the MP for Charlbury happens to be our current Prime Minister so there’s some incentive to do a good job!
Timescales have become very tight and it’s all the fault of the Romans. Apparently, they brought with them edible Roman Snails. They can be up to 50mm in diameter and there is a £2,000 fine for every one intentionally killed; you guessed it, significant quantities of healthy snails were found just where the new platform is to be located.
Under guidance from Network Rail’s environmental consultants, fingertip searches were organised, the snails retrieved and successfully relocated.
Just to make things even more challenging, our old friend the Great Crested Newt put in an appearance, along with lizards, slow worms and grass snakes. It was an environmentalist’s dream location and, to top it all, a badger set nearby had to be resited.
All change
A new platform is being provided at Ascott-under-Wychwood Station and the existing one extended by 10m; the adjacent MCB level crossing is being fully upgraded and widened to accommodate the second track.
During the blockade, S&C will be installed at Charlbury but removed at Ascott, the second track which has already been laid will be aligned and tamped, and the signalling commissioned. This new five-mile section of redoubled line will have a hugely positive impact on services as they build up to the next and final stage – the 15-mile stretch between Moreton-in-Marsh and Evesham.
Honeybourne Station will have a new footbridge similar to Charlbury. Also, one side of a currently redundant island platform will be refurbished and brought into service. There are long-term aspirations for the other side too.
As David Northey explained to me, the new bridge constructed there used to span another railway which provided a route between Cheltenham and Stratford-upon-Avon, with a connection to Honeybourne Station on the Oxford Worcester and Wolverhampton Railway.
The island platform could accommodate the future expansion of the heritage line between Broadway and Honeybourne, part of the Gloucestershire Warwickshire Railway.
Some existing sidings will be renewed and refurbished to provide stabling facilities for tampers, stoneblowers and the like, with one long siding to accommodate an HST if required. Associated S&C work, involving the installation of two crossovers, will be included.
Two level crossings at Blockley and Chipping Camden will be renewed with manually-controlled barriers and CCTV coverage, plus a third one at Clayfield where an automatic half-barrier crossing will be doubled and completely renewed.
Moreton-in-Marsh signal box will remain a mechanical box and one new mechanical signal will be erected, putting history into reverse! All the other new signals will be modern LEDs. Evesham signal box will be changed from mechanical to an NX panel as described for Ascott. Sidings there will be removed.
Mechanical signalling skills
After all this work has been completed, the 16-day blockade will commence on the 6th August when 15 miles of double track will be aligned, tamped, stressed and welded.
A single-to-double lead will be installed at Evesham. Mechanical alterations to the signalling will be completed by Network Rail engineers, a rare skill, and then the work is complete apart from the clearing up and fine tuning.
As always, there is still a lot to do and not a great deal of time to do it in. David Quintin is confident about the final outcome based on the strength of a good team ethos which is led by Ross Mahoney, Project Manager for Network Rail.
According to Ross, the contribution of all the team’s component parts has ensured that this project is progressing well. There have been a vast number of contractors engaged in work of varying size and complexity, primarily Amey and AmeyColas but supported by Carillion, Birse, Tony Gee and Partners, ADAS and Network Rail Maintenance.
The relationships built between all parties have been extremely positive.
Ross adds that a key ingredient to the success so far has been the spirit of collaboration between Network Rail and First Great Western. The TOC has been heavily involved; so too have those who live and work thereabouts.
Accidents and incidents are minimal, the local wildlife seems to be well catered for and the horticultural college will soon have its own plot of land on which it can show off its skills.
The Cotswold community has a significantly improved rail service to look forward to so hopefully there will be a successful outcome for everyone. All the signs indicate that this will be the case.
