The world’s largest operational mechanical signal box has received a comprehensive makeover after its most extensive refurbishment in over a decade.

In the heart of railway history, where time seemed to stand still, a meticulous project was underway to update and breathe new life into the timber windows of a cherished signal box. Nestled within the intricate web of railway tracks, this structure carried the weight of the past, and yet, with careful consideration, it embraced the future.


We’ve been part of the £250,000 improvements to Severn Bridge Junction, ensuring its continued operation well into the future.

Situated just beyond Shrewsbury railway station, this 117-year-old, grade II listed structure serves as a crucial link for both passengers and freight travelling between Wales, the Borders area, and the rest of Britain.

Retaining its historic charm, the building, with its 180 original levers dating back to 1903, stands as a testament to railway history. Present-day signalers adeptly utilize 89 of these levers to coordinate the movements of approximately 280 trains daily.

The task at hand involved a delicate dance between preservation and modernization. The timber windows, original to the box’s inception, received a thoughtful upgrade to enhance both aesthetics and functionality. It wasn’t merely a renovation; it was a testament to the commitment to maintaining the historical integrity of this iconic signal box.


Severn Bridge Junction, a prominent and visually striking signal box, holds a distinctive place in our railway heritage. Recognizable to many from its appearance in the inaugural series of “The Architecture the Railways Built” Yesterday, this three-story structure commands attention as it stands amidst the tracks outside the station. This location once buzzed with significant commercial activity.



In collaboration with the Railway Heritage Trust, our refurbishment initiative has impeccably weatherproofed the entirety of the structure. Originating from the building’s opening in 1904, the outdated single-glazed windows have been meticulously replaced with Ventrolla’s patented draught-roofing system and double-glazed units.

Preservation and Craftsmanship

Engineers, craftsmen, and preservationists converged, working in harmony to ensure that the soul of the signal box remained intact while ushering it into contemporary times. The aroma of freshly treated timber wafted through the air, intertwining with the echoes of bygone locomotives. Each window, weathered by years of service, became a canvas for a careful blend of tradition and innovation.

The selection of materials was a nuanced process – timber that echoed the essence of the original, yet fortified to withstand the demands of the modern climate. The goal was not just to replace but to seamlessly integrate these updates, preserving the box’s character while fortifying it against the ravages of time.

As the refurbishment progressed, the careful dance continued – a blend of history and progress. The updated timber windows stood as a symbol of resilience, a bridge between eras, allowing the signal box to tell its story for years to come. Passengers, both then and in the future, witnessed a harmonious marriage of tradition and technology as they traversed the railways, guided by a signal box that stood as a living testament to the enduring spirit of railway heritage.


The meticulous restoration extends beyond window replacements. Noteworthy enhancements involve the introduction of new timber cladding and essential repairs to the external walkway gantry. An extensive exterior repainting endeavour was undertaken, expertly preserving the iconic Shrewsbury signs that warmly welcome and bid farewell to passengers traversing the historic town by rail.

Darren McKenna, Network Rail’s asset engineer, remarked,

“The gantry repair was a big job and involved rope access teams working day and night to strengthen and replace the boards.

“We gave very careful consideration to a sympathetic repair that has managed to maintain the building’s Edwardian character while securing its future for many years to come.”

A thoughtful approach was employed in executing a sympathetic repair, preserving the Edwardian charm of the building while ensuring its sustainability for years to come. Andy Savage, the executive director of the Railway Heritage Trust, expressed his “delight” with the restoration efforts. He commended the meticulous attention given to the box’s restoration, particularly emphasizing the care devoted to revitalizing the walkways surrounding it.

The project at a glance

Engineers worked for more than 300 days to restore the exterior.

The box is grade II listed so a conservation officer pre-approved all plans to ensure the building maintained its listed status.

The Railway Heritage Trust – funded by Network Rail – contributed £50,000 to the new windows. The trust had previously contributed about £100,000 to the station’s canopies in 2018 to 2019.

The box sits on a triangle of land between railway tracks, making access challenging.


Andy said: “So many boxes are so close to the track that you need possession of the line. Here, constructing the scaffolding was more difficult as there was a certain amount of safety work in getting the material on and off the site, but once it was up you could carry on regardless, as the box is several metres away from the tracks.”

You can tell which company built a signal box just by looking at it; each railway company had its own distinct design.

Severn Bridge Junction Box, built in the early years of the 20th century is a standard London & North Western Railway design, “although it is absolutely huge” says Andy.

He said: “The L&NWR boxes had a characteristic brick-base with a wooden upper part and gable ends: if you look at the boxes along the North Wales coast … most places had basically the same design, although they are much, much smaller.”


The Project Won the ‘National Rail Heritage Signalling Award 2021 at the National Railway Heritage Awards (NRHA)


Network Rail is basking in the glow of acknowledgement for the £250,000 rejuvenation effort directed at one of Britain’s most celebrated signal boxes.

The Severn Bridge Junction Signal Box, an illustrious landmark in Shrewsbury, has claimed the prestigious ‘National Rail Heritage Signalling Award’ at the 2021  National Railway Heritage Awards (NRHA). Revered as one of the globe’s most captivating signal boxes, the accolade underscores its significance on the world stage.

Established in 1979, the NRHA distinguishes itself by conferring awards for the restoration and repurposing of segments of railway-built heritage. As the sole awards body exclusively devoted to recognizing and championing excellence, it plays a pivotal role in nurturing best practices in the restoration and upkeep of Britain’s cherished railway heritage.

Challenges on The Track and In the Air

James Walsh, regional asset manager at Network Rail said:

“This recognition a testament to everyone who worked tirelessly at every stage of the refurbishment.

“Working on a fully operational signal box, during a global pandemic, the teams overcame challenges and managed to deliver a superb project, making this world-famous signal box fit for the future and much more comfortable for our signallers who work there

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