Technical Memorandum 6 – Minimal-Dig / Slab Track / Glue-in-Road Track Systems
Subject: Birmingham Tramworks Show Utilities Don’t Always Need to Be Moved: Minimal-Dig Track Methods in Action – A UK & International Perspective
Date: June 2025
Prepared for: Policy Makers and Infrastructure Planners / Bristol and Bath Tram Association / West of England Transport Association
Recent phases of tram construction in Birmingham and Edinburgh demonstrate that it is entirely possible to install tramways without relocating underground utilities. By using modern slab track and embedded rail systems that require only shallow excavation, the West Midlands Metro project has shown that deep trenching and costly utility diversion can in many cases be avoided—especially in sensitive, high-density urban environments.
This approach is not new to the continent. The city of Strasbourg in France pioneered the extensive use of slab track and shallow construction methods for its tram network, particularly during its revival in the mid-1990s. Facing a dense urban environment with numerous existing utilities, Strasbourg’s engineers intentionally designed their tram lines to be built with minimal excavation, effectively laying track directly over existing infrastructure to avoid extensive and expensive utility diversions. This approach significantly contributed to the rapid and cost-effective expansion of their system [6].
Beyond European examples, companies like TIG/m (The International Group for Mini-Trams) are at the forefront of demonstrating extraordinary rates of progress with minimal-dig track technology. TIG/m specializes in self-powered, wire-free tram systems that utilize very shallow track forms, significantly reducing the need for utility relocation. Their methods allow for rapid installation, often with pre-cast elements, dramatically shortening construction times and minimizing disruption.
For instance, TIG/m has deployed its systems in various international locations, including Aruba, Dubai, and Qatar, where rapid installation and minimal impact on existing urban infrastructure were paramount. These projects highlight the ability to lay track with exceptional speed – in some cases achieving rates of hundreds of meters per week for double track, a pace vastly superior to the months or even years often associated with conventional deep-dig tram construction that necessitates extensive utility diversion. This is often achieved by employing specialized machinery that can precisely cut grooves for rail insertion, followed by the placement of pre-cast track sections, often without the need for wholesale road closures [7, 8].
One clear example in Birmingham is the Westside Metro Extension, where a floating track slab system was employed along the first 320 metres of the route. This method involved installing pre-cast concrete slabs directly over the existing road surface, requiring only a shallow excavation. Crucially, this avoided the need to relocate buried utilities—a process that normally adds significant time, cost, and disruption to tram projects [1].
Similarly, on Corporation Street, when sections of track were recently replaced, the old rail and road surface were removed and new rails were laid on modular concrete track bases. The concrete surface was then reinstated around the rails. This work involved minimal digging and was carefully engineered so that underlying utility services did not have to be moved [2]. The project was completed faster and with less disruption than a conventional deep-trench build would have required.
This contrasts starkly with more traditional tram construction practices seen elsewhere in the UK, notably the original Edinburgh tram scheme’s first phase. The initial Edinburgh project, which began construction in the late 2000s, faced severe delays and massive cost overruns, with unmapped and extensive utility diversions being a primary culprit [9, 10].
However, lessons were learned. For the more recent Edinburgh Tram York Place to Newhaven extension, completed in 2023, there was a conscious effort to adopt construction methodologies that minimized utility interference. While some utility diversions were still necessary, the project largely employed slab track systems (specifically Pandrol QTrack), which encapsulate the rail in a reinforced concrete slab. This ‘one dig’ approach allowed for a significant reduction in the scale and extent of utility relocation compared to the original phase [11, 12].
A particularly innovative example of minimal-dig track design is the Coventry Very Light Rail (VLR) project. Developed by Warwick Manufacturing Group (WMG) in partnership with Rendel and Ingerop, the Coventry VLR track system is designed to be exceptionally thin—around 30 cm deep, thanks to its Ultra High Performance Fibre Reinforced Concrete (UHPFRC) construction. This allows it to be laid directly over most existing utilities, drastically reducing the need for costly and time-consuming diversions [14, 15, 16].
The Waybeam track system, under development, also exemplifies this shallow-dig approach, offering modular pre-cast troughs designed for ease of installation and minimal utility impact. A test track has been constructed at Tyseley Energy Park in Birmingham [17, 18]. Because this system is essentially two narrow self-supporting beams, if utilities do need attention, then the soil can be excavated under and around them. Alternatively, entire 8 m sections can be easily removed.
Ultra-minimal systems like LR55, which use glue-in rails and even shallower trenches, are designed for very long service lives, with one notable embedded rail implementation having lasted over 25 years. Birmingham has adopted slab and embedded systems that deliver many of the same benefits [5].
Conclusion
Birmingham’s and Edinburgh’s tram extensions offer real-world proof that tramways can be installed without relocating utilities, provided modern shallow-dig track systems are used. This approach not only reduces construction time and cost, but also dramatically cuts disruption to traffic, businesses, and residents. These successful applications, following in the footsteps of pioneering projects like Strasbourg and rapid deployment by companies like TIG/m, and the innovative VLR approaches in Coventry and potentially with Waybeam, show that smart tram construction is both feasible and efficient.
References
- CiTTi Magazine. (2021). Birmingham Westside Metro extension utilises floating track slab.
- Midland Metro Alliance. (2023). Corporation Street tram track completed.
- New Civil Engineer. (2023). Birmingham Metro section main works complete.
- Dumitriu, S. (2023). Why do trams cost more in the UK?
- Bath Trams. (2024). LR55 Easy-Install Report.
- White, P. (2009). Public Transport: Its Planning, Operation and Economics. Routledge.
- TIG/m. (n.d.). Technology.
- Bath Trams. (2023). TIG/m embedded track case studies.
- Edinburgh Tram Inquiry. (2023). Final Report.
- Edinburgh Tram Inquiry. (n.d.). Tram Utility Diversions.
- Rail UK. (2021). Extending Edinburgh’s Trams.
- Edinburgh Trams. (2023). Trams to Newhaven.
- Rhomberg Sersa. (n.d.). Edinburgh Tram.
- WMG, University of Warwick. (2025). WMG’s CVLR Role.
- Coventry City Council. (n.d.). Coventry Light Rail.
- Colas Rail UK. (2025). CVLR Award.
- Ultra Light Rail Partners. (n.d.). Technology.
- Waybeam Ltd. (n.d.). Track Technology.
- WMCA. (2023). CVLR Vehicle Test.
Full manufacturer/system appendix available on request.
