The Great Western Electrification Programme

Fast-tracking passengers into the future

Modernising the Swindon to Bristol railway, offering millions of passengers a year faster, greener, quieter and more reliable journeys.

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The Great Western Electrification Programme Project summary


Network Rail Limited

Project value


Services provided

Consult, Project and programme management


Transport, Rail


UK and Europe

Project timeline

Start date
October 2013

Project story

As the appointed development and delivery partner for the electrification of the highly complex Great Western Main Line’s Bath Corridor, we drew on our expert knowledge to deliver this project on time and with significant cost savings.

As the route crosses a World Heritage site in Bath and an area of outstanding natural beauty, we gave significant consideration to environmental affects and amended more than one hundred structures before the work could take place safely.

To enable room for new trains and overhead electric equipment, we lowered the track under 115 bridges and parapets and along 1.83 miles inside the famous Box Tunnel.

Using our expertise, we avoided long programme delays through careful planning and stakeholder negotiations, and have delivered the design programme ahead of schedule by developing alternative design solutions.

This is the largest scale of works to take place on the Western route since Brunel built it.

Project stats

235miles of track electrified
11m passenger journeys improved each year
£16m savings through value engineering

Points of note

Added extras

As delivery partner to Network Rail, we’re oversaw the delivery of the structures and clearances portfolio – ensuring that it was possible to install overhead line equipment (OLE) and wires along the 235 mile (380km) track. We also monitored building and civils activity at stations and along the route. And we have identified access points for OLE plant, requirements for track lowering and areas needing clearance for OLE installation.

Saving £16m

Around 150 overhead power lines were originally identified for relocation but, with the process to arrange outage dates with National Grid potentially taking five years, this would have delayed the programme. Our experts therefore reviewed the plans and came up with a solution that left some cables in place. We have identified a further four areas where similar solutions could be implemented, which together will save around £16m.

Trained utilities expertise

In addition to project and programme management support, we put our utilities team to work on this mammoth project. They liaised with contractors and electricity distributors, leading complex legal discussions. One successful outcome was achieved through intensive negotiations with an electricity provider. Their agreement that high voltage overhead cables would be diverted in time for electrification of the train test track avoided programme delays.

Box Tunnel

To enable enough space for electrical equipment to be run overhead in the historic Box Tunnel, we lowered 1.83 miles of track by 24 inches. The tunnel, that runs through Box Hill in western England was built in 1841 under the direction of the railway's engineer Brunel.

“Mace’s Utilities Management Service team has already made a significant impact in the delivery of utilities diversions, which has been welcomed by our project managers, contractors, and utility companies alike. Its key contribution is enabling the GWLE delivery programme to stay on track – a stunning success, well done.”