Combating the cold weather
4 December 2013 • Author(s): Edd Stewart and Clive Roberts, Birmingham Centre for Railway Research and Education, University of Birmingham
With a national rail network extending from Penzance in the south to Thurso in the north, the vast majority of the UK’s railway infrastructure rests in a moderately agreeable band between 50.12° and 58.59°. Even in this comparably comfortable region, however, we are still at the mercy of the seasons. Spring rains threaten embankments and floods in one part of the country can have countless knock-on effects elsewhere. In the summer, our comparably moderate maximum temperatures still bring the risk of buckled rails. In the autumn we must contend with issues of high winds, adhesion, and the infamous ‘leaves on the line’. And in the winter we are plagued by both operational and maintenance disruptions caused by ice and snow. Since 2006, the Birmingham Centre for Railway Research and Education (BCRRE) has been undertaking work to understand and mitigate the effects of ice and snow on the UK’s railway network. While some of this has involved taking measurements from the live railway, the group has steadily been developing a suite of facilities and standard tests which can be used to evaluate the winter resilience of a number of components of the railway infrastructure.
The vast majority of the UK’s third rail network is located south of London where it makes up a significant portion of the lines. The network itself is configured as a top running conductor rail electrified at a nominal 750 V DC. This means that the contact point between the train’s collector shoe and the third rail is on the rail’s top surface. This configuration can have significant disadvantages in winter conditions as ice can form on the surface of the rail and then act as an insulating layer between the supply rail and the train. For this reason, top running third rail systems in parts of the world with climates any worse than the UK are often shrouded against snow or ice formation.