New standards form our ongoing response to Victorian infrastructure

The Victorians had considerable vision and technical prowess and left us a legacy of several large bodies of infrastructure, such as underground water pipes and extensive rail routes. Although this legacy is very welcome and highly valued it also has its limitations. Repairing underground Victorian pipes is a considerable challenge for the water industry and electrifying extensive Victorian routes is an ongoing challenge for rail.

The rail network laid down by the Victorians suffers from constraints for new technology including small tunnels which have little space between them and the trains which pass through them, particularly the vehicle’s sides and its roof. Similarly, there are many road and foot bridges which cross over the railway. Again, there is often little space between them and the trains which pass beneath them. Other challenges include routes with steep sided cuttings and embankments. In urban areas we also have housing and other developments built very close to the railway boundary. Each of these probably reduced the costs of construction and maintenance for the Victorians and was therefore a good idea at the time, but this was done at the expense of unforeseen future developments. Indeed, other industrialising nations in the 19th century also built their own railways, but the rail network in the UK is recognised as being particularly constrained, even by 19th century standards. 

These constraints, which are hard-wired into much of our existing railway, make it particularly challenging for the railway to be innovative. AC electrification is one such case. Overhead contact line (OCL) is positioned above the trains through which electricity is conducted, with train-mounted pantographs making contact with it. Support structures are also necessary to keep the OCL in place, and all this is needed in an environment using space the Victorian railway does not always provide! This means that adding AC electrification to the existing rail network is itself a significant technical challenge and has often resulted in expensive changes to existing assets. In some cases, these assets are of historical and architectural significance, such as Victorian bridges and tunnels.

Despite this, increased AC electrification of the GB network has, for many years, been accepted as the best approach for much of this network. One approach where insufficient space is available, is to raise bridge heights by modifying it or in some cases rebuilding the complete structure. It’s very impressive that this can be done but is very expensive and highly disruptive to users and local communities. So, a better approach was needed.