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Forth bridge

Bridges, tunnels and viaducts

It’s our job to look after the thousands of structures across our network

Many of the bridges, tunnels and viaducts on Britain’s railway are from the Victorian era. Being responsible for this national heritage is both a privilege and a challenge.

We’re proud to look after some of Britain’s most admired and celebrated structures. These include the Forth Rail Bridge, which was the first major structure in Britain to be made of steel, and Brunel’s Box Tunnel, between Chippenham and Bath in Wiltshire, which was the longest railway tunnel ever built at the time of opening.

But the positive aspects of looking after such iconic, historical landmarks are offset by the challenges they present. Some of these structures are very old, so are vulnerable to extreme weather conditions and often need to be renewed. They may also need to be reconstructed; many bridges aren’t high enough to fit the overhead electrical equipment that’s required to power electric trains.

Fixing and futureproofing our infrastructure

Our asset teams monitor our 40,000 bridges, tunnels and viaducts, checking structural aspects, assessing whether they can accommodate new electric trains and those carrying freight. They also carry out repairs as required.

Some of our recent works

Repair work

We carried out an intensive seven-week engineering project to repair the Victorian-built Lamington Viaduct, which carries the West Coast Mainline over the River Clyde, after flood damage had severely weakened its structure.

Refurbishing structures

We completed a £17m project in Cheshire to protect the county’s most iconic railway bridges and viaducts from the weather for decades to come, including repairs to brickwork by waterproofing it and removing water stains.

Upgrading tunnels

We’ve upgraded the 130-year-old Severn Tunnel ready for electrification of the South Wales Mainline. Our work included removing four-and-a-half tonnes of soot from the tunnel and making sure the existing brickwork was secure before drilling the thousands of holes needed for the specialist overhead line equipment.

Lowering track

Increase in demand for rail freight means we need to make sure our network can accommodate more of the wider, taller and heavier freight trains. In the south west, we lowered approximately one mile of track at Dundas Aqueduct so that the line could be used as a diversionary route for taller freight trains in the future.

Bath and North East Somerset works (timelapse)

This timelapse video below shows the preparation for electrification of the Great Western Mainline at Bath and North East Somerset.

Find out more about the project


Exploring new technologies

We’re finding new ways to increase the clearance needed for electric trains so that fewer bridges need to be reconstructed.

One technique being trialled jacks the bridge arches on a masonry bridge vertically to enlarge the space below. This approach has two benefits: the original bridge doesn’t have to be demolished and rebuilt and there is no need to close the railway line for several days, which reduces the impact on passengers.