Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Chilterns' silver lining

RAIL: Chiltern Railways' model network modernisation is being achieved at the cost of some short term pain. Andrew Mylius reports.

Here's something to enrage rail commuters:

From now until August, rail passengers using Chiltern Railways' services between Birmingham and London Marylebone will be treated to regular delays. Late night services will be cancelled and there will be no trains at weekends. To fan customer frustration further, from 20 April to 6 May, Chiltern will be diverting all its services via Oxford, Didcot and Reading to London Paddington, adding a significant chunk of extra journey time.

After establishing credentials as a model rail operator, Chiltern's sudden slide into chaos will be a shock - enough to drive people to their cars, acknowledges head of operations planning Martin Talbot.

Chiltern is laying on buses and taxi shuttle services to help minimise damage to its customer base. But beyond August, Talbot is confident the firm - which has just won a 20 year franchise extension from the Strategic Rail Authority - can not just woo disgruntled passengers back but that it will be able to win more customers than it now carries.

The five months of aggro Chiltern has in store is being caused by line doubling on a notorious bottleneck between Aynho and Bicester. Built as twin track at the turn of last century, the route was written off as commercially unviable in 1968, and one of the lines torn up. Since winning its operating franchise seven years ago, Chiltern has been limited to running a maximum of one train every 10 minutes - three trains in either direction every hour.

Chiltern region has seen a rail renaissance, stimulating demand for faster, more frequent services into and out of London.

Doubling the line will create capacity for twice as many trains. Track improvements will allow running speeds to be increased from 125km/h to 145km/h. And where at present a signalling failure, track problem or train breakdown on the Aynho-Bicester section can jam the network up to Stratford on Avon, Coventry and Rugby, once the doubling is complete trains will be able to leapfrog around trouble spots, making the route vastly more reliable.

Chiltern Railways has formed an alliance with Railtrack, contractors GTRM and Birse, and signalling firm Westinghouse to tackle the 15km project. With a £60M price tag, some impressive feats of civil engineering might be expected. However, no large scale structural works will be required - there are no bridge replacements or major tunnel repairs to be carried out.

Instead, cost reflects the unusually fast pace at which work is being carried out, says Railtrack engineering manager Shaun Winfield. The alliance is racing to have the new line in operation by 10 August, when the southern section of the West Coast Main Line (WCML) will be shut for upgrade work. Capacity will be needed on the Chiltern network to move people between Birmingham and the capital.

Learning from teething problems on the WCML, the Chiltern alliance is opting for simple, proven technical solutions. Its schedule offers no scope for redesigning, trouble shooting or replacing faults in the system.

Westinghouse has already installed new communications and signalling cables in preparation for the work ahead.

Although existing mechanical and electrical infrastructure was far from obsolete, this has been needed because much of it was buried in the redundant track bed. M&E operations were completed two weeks ago.

Since 1968 major maintenance on the Aynho-Bicester section had all but ceased. Cut slopes slumped, encroaching on the track bed, and over the years the one remaining track has been realigned, snaking across from up to down sides.

Regrading and soil nailing will be carried out, pushing cut slopes and embankments back into acceptable profiles and preventing further movement so that the twin track can be accommodated. At the same time, collapsed and root-damaged drains will be repaired or replaced to overcome the acute waterlogging problems encountered on parts of the route.

Where line is on its original alignment, GTRM is already forging ahead with excavation of old track bed in preparation for the laying of new ballast. As much new line as possible will be laid parallel to the existing tracks during night time and weekend possessions.

Possessions are also being used to renovate a section of tunnel at Ardley and two brick viaducts at Souldern.

During the 17 day service suspension the alliance must connect new and existing stretches of track, using a tamping machine for compaction to avoid the need for speed restrictions once trains start running again.

Branching out

To give passengers an alternative route between Birmingham and London after the WCML upgrade works close its southern section on 10 August, Chiltern Railways was forced to accelerate its programme of work. The operator had set out the scope of work, and design and preliminary works were under way well before it signed its 20 year franchise extension contract with the Strategic Rail Authority (SRA) last month.

The Aynho-Bicester track doubling is just a small part of a huge programme which, if SRA approval is granted, is to be rolled out over the next few years.

A major upgrade of the Aylesbury-London line.

A new line to Oxford.

Reopening of the old Great Central route to a station near the M1/M6 intersection.

Reopening of the AylesburyBletchley/Milton Keynes route.

Quadrupling of track through Beaconsfield and London's West Ruislip areas.

An interchange station at West Hampstead, London.

A new 'park and ride' station at Aylesbury.

Additional signalling between Bicester North and High Wycombe.

Reopening of the old Moor Street terminus station in Birmingham, 2003.

£22M of investment in new or improved depots.

Creation of transport interchanges at High Wycombe and Banbury stations.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.