Doncaster PSB: Delivering Critical Refurbishment on a Live Railway Facility - CML Civil Engineering

CML is currently delivering a significant refurbishment programme at Doncaster Power Signal Box (PSB), with works focused on protecting and improving the building’s roof and, ultimately, safeguarding what it houses.

The scope includes the reconstruction of the existing parapet walls, refurbishment and replacement of the roof coverings, associated repairs, and the installation of extensive scaffold with roof cover protection. Works commenced onsite in May and are expected to complete in early 2027.

A Piece of Railway History

Doncaster PSB holds a notable place in railway history – it was the third major signal box to be commissioned on the East Coast Main Line, underlining its long-standing importance to the operation of this critical route.

Working on a Live, Operational Railway Facility

One of the biggest considerations on this project is that Doncaster PSB remains fully live and operational throughout our works. The PSB plays an important role in the operation of the railway around the East Coast Main Line, so maintaining its operational capability has been at the forefront of our planning from day one.

Delivering this safely and effectively has required a highly collaborative approach between CML, Network Rail, the PSB team, our designers and our wider supply chain. Every activity is carefully planned and coordinated to ensure construction works do not interfere with the day-to-day duties of the operational staff working inside the building.

Materials and Techniques

While much of the refurbishment follows established, proven methods, the project has also called for some considered technical solutions:

Parapet reconstruction has been carried out using Class A engineering bricks, chosen for their strength and durability.
During emergency and investigation works carried out last year, the team identified that the building had no wall ties in place. This was reported to the client, and following their instruction, Helifix ties were installed to reinforce the structure.
The existing roof system is being fully stripped and replaced with a new tapered insulation roofing system with a Caltech finish, improving both thermal performance and weathertightness.
The roof has been designed to fall towards the car park side of the building, where new rainwater goods – including hoppers, gutters and downpipes – are being installed to manage water run-off effectively.
Once the roofing works are complete, a Kee Guard handrail system with self-closing gates will be installed. This will provide safer, easier access for any future maintenance to the roofs and building.
An element of underground drainage renewal also forms part of the scope. This work can only be carried out once the main works are complete and the scaffold has been dismantled.

The building’s exterior is also being refreshed as part of the works. Historically, Doncaster PSB was clad in black ceramic tiles, though these have been removed over the years, leaving the two-storey building painted. As part of the current package, CML will remove the remaining tiles and repaint two sides of the building with a Sandtex finish.

Key Milestones

A major early milestone was the successful installation of scaffold and access arrangements around the PSB. Given the nature and location of the building, this required considerable planning to provide our workforce with safe access to the roof and external elevations, while maintaining access and operational requirements for the PSB throughout.

Following completion of the scaffold, the project team safely removed the previous temporary protection and completed reconstruction of the parapet walls.

Progress to date includes:

Scaffold and access arrangements fully established
Temporary protection removed
Parapet reconstruction completed
Roofing works progressing from next week

Collaboration at the Heart of the Project

Perhaps the most positive aspect of the project has been the way the team has approached the challenges of working on a live, operational building.

Unlike an unoccupied construction site, activities cannot simply be planned around what is most convenient for the construction programme. The team must continually consider the operational requirements of the PSB and understand how each activity could affect the people working inside.

Potentially disruptive activities are planned and communicated well in advance, with careful consideration given to noise, vibration, access, deliveries, lifting operations and the interaction between different trades on site.

Where unforeseen conditions or changes have arisen, the approach has been consistent: stop, review the issue with the relevant parties, and agree a suitable solution before progressing. This collaborative mindset has helped the team overcome a number of planning and sequencing challenges, without losing sight of safety, quality or the operational needs of the railway.

Recognition from Network Rail

The strength of the project team’s approach has been reflected in feedback from both senior management within CML and directly from the client. Following a recent site visit, Charlie Holl, Buildings & Civils Project Engineer, Network Rail commented:

“I was delighted by the site visit yesterday to Doncaster. It is possibly the best site set up and evidence-based documentation site that I have visited in my time with Network Rail. A credit to the site management team. Please can you pass this on to all concerned.”

Looking Ahead

With scaffold and access arrangements established, temporary works removed and parapet reconstruction complete, the project is progressing positively, with roofing works set to begin next week.

The relationship and collaborative working between the CML project team has been central to the project’s success so far. The team onsite continue to do a fantastic job, taking real ownership of the project and delivering to a standard recognised by both CML’s senior management and Network Rail.

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