Links to other memoranda in this series:

1. ComparativeBenefits of Trams and Buses in Urban Public Transport
2. Dispelling the myth that trams need special seperate segregated path through traffic
3. “Glue-in-the-Road” TramTrack Systems versus Conventional Deep Excavation Methods
4. Why trams are essential to improve city productivity
5. Overhead wire-freeTechnologies for Tram Propulsion
6. Birmingham Tramworks Show Utilities Don’t Always Need to Be Moved: Minimal-Dig Track Methods in Action – A UK & International Perspective

Technical Memorandum 3 – Embedded “Glue-in-the-road” Tracks

Subject: One – Dig/ Shallow / Modular /Embedded Track / “glue in road” / Slab tracks Track Systems versus Conventional Deep Excavation Methods
Date: June 2025
Prepared for: Bristol and Bath Tram Association / West of England Transport Association

Executive Summary

Urban tramway construction has faced two major challenges: cost and disruption to traffic and commerce. Traditional deep excavation methods—requiring extensive service diversions—have historically led to delays and significant budget overruns. Modern embedded track systems, installed directly into the road surface, provide a faster and more cost-effective alternative to mitigate these issues.

A key example of these challenges is the Edinburgh Trams Phase 1, which suffered five-year delays and a final reported cost exceeding £1 billion, far surpassing its initial £545 million budget due to unforeseen utility complications and complex ground conditions [1][2]. In contrast, Edinburgh Trams Phase 2 (Newhaven extension) was completed on time and within its revised £207 million budget for 4.6 km, benefiting from an improved utility mapping process and a “one-dig” embedded track approach to minimize disruption [3][4].

This memorandum compares embedded tram track systems—where rails are installed in shallow concrete slabs or directly into slots cut within the road surface—with the conventional British approach of deep excavation and full utility diversion. Embedded systems have demonstrated faster installation, lower costs, reduced need for utility diversion and reduced urban disruption.

International case studies confirm that embedded track methods significantly outperform deep excavation in installation speed, often avoiding costly and time-consuming utility relocations [5][6]. While embedded systems frequently bypass extensive service diversions, localized underground conditions may sometimes require targeted adjustments. Thorough preliminary utility surveys remain essential for accurate project planning.

Comparative Costs and Installation Rates of Embedded Tram Track Systems

2.1. Definition of “Track-Only” Costs

For this comparison, track-only costs encompass all physical civil engineering works directly related to tram track installation, whether using embedded or deep-dig methods.

Included: removal of road surface, excavation (depth varies by method), sub-base preparation, track slab, rail installation, surface reinstatement, service diversion if necessary.
Not included: power systems, stops, signalling, rolling stock, project management. This ensures direct comparability of installation rates and costs between embedded and deep-dig track approaches.

2.2. Embedded Track System Types

Shallow / Modular Embedded Track / “glue in road” / Slab tracks (Minimal-Dig)
Typical depth: ~150–250 mm
Installed just below the existing road surface
Designed to avoid or bridge over utilities but permit rapid removal for services maintenance in the future
Uses pre-cast modular slabs, beams, or thin in-situ slabs
Advantages:

• Minimal utility diversion
• Lower construction impact
• Faster installation
• No requirement to disturb ground outside the line of the tram
  Track-only cost: £1.5M–£3M/km
  Installation rate: 30–130+ m/day

Conventional Deep-Dig Embedded Track
Typical depth: ~400–600 mm
Requires full road excavation
Involves relocation or protection of underground utilities into new adjacent ground adjacent to the track
Typically uses in-situ reinforced concrete slab
Disadvantages:

• Slow construction
• High disruption
• Substantial utility-related delays and costs
  Track-only cost: £5M–£10M/km
  Installation rate: 4–8 m/day

2.3. Comparative Table: Installation Rates and Costs (General)

Comparative Case Examples

Discussion

Embedded slab systems have been shown to reduce construction time by a factor of 5–10 compared to traditional deep digging methods, owing to shallower excavation and less complex utility management. By minimizing or avoiding utility diversions, embedded track projects achieve substantial cost savings, as utility relocation is a significant component of conventional tramway costs.

However, local underground conditions can require partial utility diversion, emphasizing the need for comprehensive preliminary surveys. Urban disruption, traffic management complexity, and environmental impacts (such as noise and dust) are significantly lessened with embedded systems due to shorter construction periods and reduced excavation.

Challenges include design integration with existing utilities and ensuring long-term durability, especially regarding the interaction of rail and road surfaces. These are mitigated by early and accurate utility surveys, careful engineering, and the use of modern resilient track systems.

As well as reduced construction time and cost, consideration should be given to:

• Total lifecycle costs (including renewals)
• Embedded carbon emissions

The use of grout (in slab tracks) adds cost and complexity at renewal, and pre-cast concrete slabs have substantial embedded emissions. Systems such as Waybeam and LR55, which avoid grout and/or concrete slabs, may offer long-term environmental and cost benefits.

Appendix: List of Embedded Tram Track Systems

• PCAT (PreCast Advanced Track) – UK-based prefab slab system similar to Coventry VLR trackform. https://www.precastadvancedtrack.com
• Taveirne Prefab Systems – Ladder and embedded tram track units used in Belgium. https://taveirne.be/en/projects
• Tines Rail LC-L – Prefabricated track slabs for urban tramways. https://tinesrail.com/en/products-and-systems/prefabs/prefabricated-track-road-slabs-tines-tram-lc-l/
• Préfarails (Sateba) – Prefab slabs with stone sets, used in Belgium. https://www.qu4tre.be/emission/tram-en-commun/
• Edilon Sedra Corkelast® ERS – Prefab embedded girder rail system. https://www.edilonsedra.com/fr/project/solution-de-voie-prefabriquee-pour-une-installation-rapide-de-passages-a-niveau/
• Vibratec VT-Stero – Embedded trackform using girder rail. https://www.vibratec.org/fr/produit/systeme-de-voie-vt-stero/
• Waybeam – Prefabricated embedded rail slab under development https://bathtrams.uk/waybeam/
• Trampower LR55 – Lightweight modular embedded rail track in service over 29 years in Sheffield. Contractors estimate >100m/week double track without road closure. https://lr55.co.uk

7. Other Shallow Track Installs

Europe
Germany: Berlin, Munich, Dresden, Leipzig, Frankfurt (Main), Cologne, Düsseldorf, Stuttgart, Karlsruhe, Hannover, Nuremberg
France: Bordeaux, Nice, Lyon, Strasbourg, Montpellier, Nantes, Paris
UK: Manchester (Metrolink), Birmingham (West Midlands Metro), Edinburgh, Sheffield, Nottingham, Croydon, Coventry (VLR), Bradford
Poland: Kraków, Poznań, Warsaw, Bytom, Wrocław, Gliwice, Łódź, Toruń, Gorzów
Austria: Vienna
Switzerland: Various modern tram extensions
Netherlands: Various tram lines with double-block concrete slab track
Spain: Barcelona, Madrid
Italy: Florence, Rome, Milan, Turin
Turkey: Istanbul, Ankara

North America
USA: Portland (Oregon), Seattle (Washington), Dallas, Houston, Charlotte, Tucson
Canada: Toronto

Asia
China: Tianjin, Shanghai
South Korea: Seoul, Busan
Japan: Urban tram systems

Australia
Melbourne, Sydney, Gold Coast

South America
Rio de Janeiro (VLT Carioca)

References

1. McLaughlin, M. (2018). Edinburgh Tram Inquiry, Phase 1 Report. The Scottish Government.
2. BBC News. (2018). Edinburgh trams: Timeline of the capital’s controversial line.
3. City of Edinburgh Council. (2023). Trams to Newhaven Project Delivered.
4. Pandrol. (n.d.). Edinburgh Trams to Newhaven Extension.
5. International Association of Public Transport (UITP). (2013). Light Rail: A Guide to Best Practice.
6. Transport for London. (2016). Technical Specification for Embedded Rail Track.
7. Midland Metro Alliance. (2021). Birmingham Metro Track Construction.
8. Tramways & Urban Transit. (2010). Florence: A New Generation of Tramway.
9. Railway Technology. (2015). Kaohsiung Tram Case Study.
10. TIG/m. (2020). Global Project Press Release.
11. Railway Age. (2014). TIG/m Brings Battery Trams to the Caribbean.
12. Santa Cruz County Greenway. (2023). TIG/m Technology Overview.
13. Coventry City Council. (2023). Very Light Rail Overview.
14. Pade, S. (2017). Tramway Construction Costs: A European Perspective.
15. Bath Trams. (2024). Waybeam Prefabricated Track System. https://bathtrams.uk/waybeam/
16. Light Rail Transit Association. (n.d.). Strasbourg Tram Systems.
17. Alstom. (2007). Le Mans Tramway Construction Overview.
18. Railway Gazette International. (2017). Dublin Luas Cross-City Report.
19. Alstom. (2019). Sydney Light Rail: Delivering a World-Class Transport System

Links to other memoranda in this series:

1. ComparativeBenefits of Trams and Buses in Urban Public Transport
2. Dispelling the myth that trams need special seperate segregated path through traffic
3. “Glue-in-the-Road” TramTrack Systems versus Conventional Deep Excavation Methods
4. Why trams are essential to improve city productivity
5. Overhead wire-freeTechnologies for Tram Propulsion
6. Birmingham Tramworks Show Utilities Don’t Always Need to Be Moved: Minimal-Dig Track Methods in Action – A UK & International Perspective