The Anonymous Widower

Electrification Of Britain’s Railways Isn’t Easy

There are a lot of reports in the media talking about the delays in electrifying railways in the UK, like this report in the Yorkshire Post, which talks about the Trans Pennine and Midland Main Line schemes.

I have just found this report in the Rail Engineer, which talks about a forty-four day closure of the important Winchburgh Tunnel between Edinburgh and Glasgow to prepare for electrification as part of the Edinburgh Glasgow Improvement Program. The report starts with this paragraph.

A legacy of the rapid early growth of Britain’s railway network is that the UK has one of the world’s most restrictive loading gauges. As a result, typically half of the cost of British electrification projects is the civil engineering work to adapt structures to provide clearance for wires and pantographs.

As anybody who’s ever got to grips with any old building, what it looks like on the surface is very different to what is underneath.

The project described in the article is challenging to say the least. This extract describes the building of the tunnel.

Winchburgh tunnel lies at the eastern end of a five- kilometre long cutting. It is 338 metres long and was opened in 1842, having taken two years to complete. When digging the cuttings and tunnel, the contractor, Gibb and Sons, removed 200,000 tons more rock than expected and consequently made a loss.

The tunnel was cut through dolerite rock, mudstone and shale. In the middle on the nineteenth century, these oil shale deposits once made West Lothian one of the world’s biggest oil producers. This shale was also a factor in an unfortunate accident during tunnel construction in 1839 when a man was severely burnt by firedamp.

The cutting is crossed by two streams, west of the tunnel. A twin four-foot diameter cast-iron inverted syphon was provided to carry Myers Burn under the railway. Swine Burn crosses the cutting on an aqueduct that had to be re-decked as part of the EGIP electrification works. Downstream of the aqueduct is a pumping station, which drains the cutting west of the tunnel. This is an area with significant drainage issues, some of which are addressed by the tunnel works.

So making it large enough for electrification wasn’t easy. As is typical on a project such as this, concrete slab track was used. You don’t see it much on UK railways, as where it is used is generally in tunnels and other places, where you have tight clearances.

In the Winchburgh tunnel slab track was used and they are also using an overhead rail system to get the power to the train.

In searching for a good article about slab track, I found this article on Balfour Beatty’s Rail web site, which is entitled Polyurethane Slab Track.

Balfour Beatty have worked with Herriot Watt University to create a method of using polyurethane to create a method for strengthening track in awkward places.

One example describes how a bridge was improved to cope with modern loads.

While George Stephenson was a forward thinker, even he didn’t predict freight trains running at 80mph with 25 tonne axle loads over his bridge. So he hadn’t calculated for those stresses. The bridge has done a good job of coping with them for 190 years, but it was getting a bit tired. 

The article also highlights that Network Rail has 25,000 masonry arches, so you can see why there must be a need for such a technique.

The technique has also been used to increase the headrom for electrification in a tunnel on the Midland Main Line.

It’s all impressive engineering.

July 31, 2015 - Posted by AnonW | Transport/Travel | Electrification, Engineering, Tunnels