There is also an increasing issue with diesel trains “holding up” faster Electric Multiple Units (EMUs) wherever they share the same tracks, thereby constraining capacity on Britain’s already congested rail network. But with railway vehicles designed to last 30 to 40 years, diesel is not regarded as a long term solution. There have been great advances in the efficiency and cleanliness of diesel engines. With the push to electrify the UK’s mainlines, the burden on Britain’s already stretched generation and distribution networks will increase. Railways also draw large quantities of power during the morning and evening peaks, and traction loads consume just a single phase from the UK’s 3-phase distribution network, unbalancing the National Grid. The rail network also consumes a significant proportion of the UK’s overall electricity supply, estimated to be around 3 TWh (ATOC, 2007) per annum for traction out of a total of 331 TWh for the UK as a whole (International Energy Agency, 2016), i.e. There are other issues with electrification including the visual impact of overhead wires and masts, and the disruption that the installation of electrification can cause, particularly where bridge structures and tunnels need to be enlarged. But electrification is expensive, and while justifiable on heavily used lines, rural and branch lines simply don’t see the levels of traffic and revenue to justify this expense.
Electrification can help in this respect by providing high performance trains that maximise capacity and reduce pollution in our towns and cities.
The railways are under pressure to increase capacity, reduce operating costs, and cut their contribution to pollution and CO2 emissions.