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Elgin marvel

Elgin to Mossend - A main line in Scotland is being improved for heavier freight - hopefully without any disruption, reports Adrian Greeman.

The flat pack wardrobe is having unexpected influences, not least on Scotland's railways.

Scandinavian furniture firm IKEA is importing ever greater volumes of its knock down wares through the northeast coast container port of Elgin.

Trucks are increasingly jamming roads south, and relief is needed. Rail, the Scots believe, is the answer. One of the first major projects to be undertaken by Transport Scotland, the Scottish Executive's transport agency, is to upgrade the 430km east coast line from Elgin to Mossend, near Glasgow.

The route stops at Aberdeen, Dundee and other significant cities. Mossend has a big Euroterminal for rail goods.

'There is a 10% growth in freight predicted for the northeast in the next few years, ' says David Simpson, Scotland route director for Network Rail, which is overseeing the £4M project.

'I think there is potential for even more. But gauge restrictions have always limited us to small box traffic.' Rebuilding the bridges and tunnels of the narrow Victorian line would be impossibly expensive. But the gauge can be adjusted to take 9'6' (2.9m) high containers by clever track realignment, judicious lowering of track bed and replacement of concrete and timber sleepers with modern steel ones from Corus.

'They are slightly thinner, ' explains John Hughes, project manager for the scheme at the Scotland Track Renewals Company (STRC), a division of Jarvis Rail.

Simply slewing the track alignment by 100mm can provide the clearance needed between containers and the soffit of old brick arch bridges.

Although this brings up and down lines closer to the bridge's centre line, there is still enough space for two trains to pass.

Network Rail's consultant Scott Wilson Rail identied 27 overbridge sites that pinched the loading gauge, and specied the remedy. The consultant is carrying out detailed design work.

In most cases, slewing the line sufces. But at a few points, the line needs to be lowered as well as slewed.

In eight locations 'traxcavation' is taking place.

This involves removing the 350mm layer of ballast and reducing its depth by 50mm.

'We use an automatic ballast cleaning machine to riddle it on a screen and remove the degraded material, replacing it with fresh ballast, ' says Raj Sinha, Jarvis managing director for Scotland.

'In most cases, this work also means cutting rails and then later re-joining them and stressing again, ' adds Hughes. Stressing is also required after the larger slewing operations which would otherwise excessively 'stretch' the rails. 'Anything above a 100mm movement usually needs stressing, ' he says.

One of STRC's advantages in winning the work is that its sister company within Jarvis, Fastline, has a large number of the machines required for the work. This more or less guarantees sourcing the right machinery when it is needed.

But the company also had to persuade Network Rail of its planning and organisational abilities at the interviews which were held with all ve rms which prequalied for the job.

Bidding was on a combination of technical skill and price, says Hughes.

A key part of the project was that the work could be done without extended track possessions. Simpson describes this as 'a major victory'.

'Much if it can be done in standard no-train time at weekends, ' explains Hughes.

That allows a ve hour Saturday night possession - 'good for slewing works', he says.

Longer periods of eight to 54 hours are needed for more complex works, and these are slotted into the existing programme of disruptive possessions already planned for the line by Network Rail.

The possessions have been booked around two years ahead of requirement to allow for switch and crossing maintenance. By happy coincidence Jarvis is term contractor in Scotland and is carrying out this work too.

One of the most complex upgrades will involve five sites between Dundee and Aberdeen, where two other major projects are already booked in.

Synchronising site access for machines and trains between the various jobs has required intensive and meticulous planning.

All finished work must be available for immediate full speed train running at up to 160km/h. That means dynamic tamping to standard without the usual week long period of slow running to let ballast bed in.

Completion of the work will result in an extra 1.3Mt of freight using the line, says Simpson.

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