Hertford Loop - Spencer Group

Hertford Loop

The Hertford Loop is used as a diversion route for the East Coast Main Line between Stevenage and London, as well as providing a busy commuter route from rural Hertfordshire to Moorgate and King’s Cross.

With the level of traffic planned to increase on the Hertford Loop, the capacity of the overhead electricity supply had to be raised in certain locations. Spencer Group was given the contract to carry out the crucial electrification work.

Project scope

Spencer employs a large team of electrification and plant (E&P) specialists in design, management, engineering and delivery. We have a successful history of specifying, installing and maintaining electrical infrastructure on national rail networks.

This project involved the removal of 9No. stanchion mounted 150 amp boosters and the installation of 9No. Ground mounted 300 amp boosters at five locations between Crews Hill and Hertford. Associated works included new troughing routes, secure compounds and under track crossings.


Each new booster set was installed and commissioned during a 27-hour possession and isolation of the route. All the works were carried out by Spencer, utilising in-house resources.