HS2 Has Installed Its First Platforms at Old Oak Common. The Secondary Infrastructure of Britain's New High-Speed Railway Must Perform for 50 Years Underground. Here Is Why FRP Is the Specification.

Engineers have begun installing the first passenger platforms at Old Oak Common, HS2's underground super-hub in west London. Nearly 2,000 pre-cast concrete slabs are being placed within an 850-metre underground station box, 20 metres below street level, that will serve 250,000 daily passengers when complete. The secondary infrastructure of that station — grating, walkways, cable management, drainage, and access systems — will operate in one of the most demanding environments in UK civil construction: persistent underground humidity, aggressive chemical cleaning regimes, high-voltage traction power systems, and a 50-year design life. This is where the FRP specification case is most precisely and consistently made.

Published by Reinforce Technology  |  22 July 2026

Old Oak Common is the largest newly built railway station in the UK. Engineers have begun installing pre-cast concrete slabs for six high-speed platforms, each designed to accommodate 400-metre HS2 trains, constructed simultaneously as three island-style blocks within the 850-metre underground station box. The station will feature 14 platforms in total and is designed to accommodate 250,000 daily passengers, anchoring significant urban regeneration across West London. The underground station box, measuring 850 metres in length with a 45,000 square metre base slab, was completed earlier in 2025 using 76,000 cubic metres of concrete and 17,000 tonnes of reinforced steel. Tunnel boring machines launched in January 2026 are now constructing the tunnel linking Old Oak Common to Euston (HS2, 2026).

The station is being constructed by the Balfour Beatty VINCI SYSTRA joint venture, with a target completion between 2029 and 2033. Its design by WSP and WilkinsonEyre has achieved a BREEAM Outstanding rating, incorporating a vaulted roof for natural light, an open-plan layout for natural ventilation, and extensive energy optimisation systems. When operational, it will connect passengers to over 100 destinations across the UK and serve as the 42nd stop on the Elizabeth line, integrating HS2, Great Western Main Line, Heathrow Express, and London Underground services in a single interchange that will reshape passenger movement across the capital.

The construction milestone at Old Oak Common is a moment to examine what the secondary infrastructure specification of a project of this scale, complexity, and design life actually requires. The underground station environment is not simply a large building with trains in it. It is a combination of persistent humidity, aggressive cleaning chemistry, high-voltage traction power, heavy foot traffic across grating and walkway surfaces, and a 50-year operational design life that places secondary materials under sustained stress from the first day of operation. Understanding that environment precisely is the starting point for specifying secondary infrastructure that performs across the full life of one of the most significant transport investments in British history.

Engineers are installing the first passenger platforms at Old Oak Common's 850-metre underground station box. The secondary infrastructure of underground rail environments — grating, walkways, cable management, and drainage — operates in conditions of persistent humidity, aggressive chemical cleaning, and high-voltage traction power for 50-year design lives.

Why Underground Rail Is the Most Demanding Secondary Infrastructure Environment

Underground rail stations and tunnels create a combination of secondary infrastructure demands that does not exist in any other category of UK construction with the same intensity and persistence. Four specific conditions define the underground rail environment and determine what secondary materials must withstand across a 50-year operational life.

The first is persistent humidity. Underground environments trap moisture from passenger breath, groundwater ingress, cleaning operations, and the ventilation systems that manage air quality in enclosed underground spaces. Relative humidity in London Underground tunnels and stations consistently ranges between 70 and 90%, with condensation on surfaces a normal and recurring condition rather than a weather event. Secondary steel infrastructure in this environment corrodes progressively across 50 years without the atmospheric drying that interrupts the corrosion cycle in surface installations. Galvanised steel coatings in underground rail environments deplete faster than in most outdoor industrial applications, because the persistent moisture eliminates the drying periods that slow the electrochemical corrosion process.

The second is aggressive chemical cleaning. Railway stations with 250,000 daily passengers require intensive and frequent cleaning to maintain the hygiene, safety, and presentational standards that public transport infrastructure demands. Platform grating, walkway surfaces, drainage channels, and the secondary structural elements visible to passengers are cleaned with industrial cleaning agents — alkaline degreasers, acid descalers, and sanitisers — applied by cleaning contractors on daily or shift-frequency cycles. Secondary galvanised steel infrastructure subjected to this cleaning regime accumulates chemical attack at its surfaces from both the cleaning agents and the residual traffic contamination they are designed to remove. FRP's chemical resistance to the full range of cleaning agents used in UK railway station environments means it does not accumulate surface degradation from the cleaning programme that maintains the station's operational standards.

The third is high-voltage traction power. HS2 uses 25kV overhead line electrification, and the secondary cable management, structural supports, and access systems in and around the power distribution infrastructure of an underground HS2 station operate in proximity to the highest voltages in UK mainline rail. Non-conductive secondary infrastructure in these environments eliminates the earthing and bonding requirements that metallic secondary structures demand, reduces the risk of accidental current paths through secondary structural elements, and simplifies the electrical safety management of the station's complex power distribution environment (IntechOpen, 2022).

The fourth is the 50-year design life. Major UK rail infrastructure is designed and funded on the basis of a 50-year asset life. Secondary infrastructure that requires maintenance intervention before the end of that design life generates access events in an operational railway environment — one of the most controlled and expensive maintenance environments in UK infrastructure. Every maintenance access in an operational underground railway station requires possession planning, safety management, track access permissions where relevant, and the disruption to station operations that follows. Secondary materials that require no maintenance access across 50 years directly reduce the lifetime maintenance cost of the asset and the operational disruption that maintenance generates in a station serving 250,000 daily passengers.

Where FRP Is Specified in Rail and Underground Transit Infrastructure

1. Platform Grating and Walkway Surfaces

Platform edge grating, service walkways beneath platform levels, and the access grating covering the void spaces that allow easy access for services and maintenance, including electrical maintenance, beneath the Old Oak Common platform slabs are among the most directly challenged secondary infrastructure in any underground station. They carry the direct weight of cleaning equipment, maintenance personnel, and in some configurations light maintenance vehicles. They are cleaned frequently with the full range of station cleaning agents. And in the void spaces beneath platforms, they operate in the most humid and chemically concentrated part of the station environment, where drainage, electrical services, and ventilation ducts create a persistently moist, chemically complex atmosphere.

FRP moulded grating in underground rail environments provides anti-slip access flooring that does not degrade under repeated cleaning chemical exposure, does not corrode in the persistent humidity of underground service voids, and does not require the surface maintenance that galvanised steel grating accumulates across 50 years in the same conditions. The integral grit surface maintains consistent slip resistance across the operational life of the installation without the coating degradation that painted or galvanised steel grating experiences under sustained cleaning and foot traffic in humid environments. Non-conductive throughout, FRP grating in the high-voltage proximity zones beneath HS2 platforms eliminates the earthing requirements that metallic grating would demand in the same location (IntechOpen, 2022).

2. Cable Management in High-Voltage Railway Environments

The cable management infrastructure of an underground HS2 station carries a combination of 25kV traction power distribution cables, signalling and control cables, communications and data infrastructure, and the building services power distribution for the station's mechanical and electrical systems. This diversity of cable types, at voltages ranging from extra-low voltage data cables to high-voltage traction power, runs through the same underground station environment and requires cable management that is non-conductive throughout to eliminate fault current propagation between cable categories and to remove the earthing and bonding programme that metallic cable management would require across all of these voltage levels.

FRP cable trays in underground railway environments provide non-conductive cable management that does not require earthing and bonding in the high-voltage zones of the station's traction power distribution, is corrosion-immune in the humid underground atmosphere, and is approximately 75% lighter than equivalent steel cable management, reducing the structural loading on the underground station's secondary support systems where dead load is a specific design constraint (IntechOpen, 2022). The non-magnetic property of FRP is specifically relevant in signalling environments where the electromagnetic compatibility of secondary infrastructure near signalling cables can affect train detection and control system performance.

3. Structural Profiles for Secondary Framing and Equipment Supports

Secondary structural framing for equipment supports, cable management supports, signage mounting, and access platform primary framing in underground rail stations operates in the same persistent humidity as all other secondary infrastructure in the environment, with the additional constraint that secondary structural elements in passenger-facing areas must meet the finish and maintenance standards of a public transport facility designed to the BREEAM Outstanding standard that Old Oak Common has achieved. FRP pultruded structural profiles, available in consistent cross-sections and surface finishes appropriate for visible secondary structural applications, provide maintenance-free, non-corroding framing that retains its appearance across 50 years in the underground station environment without the surface treatment maintenance that secondary steel structural elements require to prevent visible corrosion in a public-facing application.

4. Drainage Channels and Station Drainage Infrastructure

Underground station drainage carries a combination of cleaning water, condensation drainage, and in stations with surface level areas, rainfall runoff. In the concentrated cleaning environments of heavy-footfall underground stations, drainage channels carry the most chemically concentrated effluent of any part of the station's secondary infrastructure, including the cleaning agent concentrations that remain in drainage flow between dilution by rinse water. FRP drainage channels in vinyl ester resin provide chemical resistance to the full range of cleaning chemistry encountered in UK railway station drainage environments, do not corrode in the persistent moisture of underground drainage conditions, and require no lining or coating maintenance across the 50-year life of the installation.

FRP cable management in underground rail environments is non-conductive in high-voltage traction power zones, 75% lighter than steel reducing dead load on secondary support structures, and corrosion-immune in the persistent humidity of underground station atmospheres across 50-year operational design lives. | Photo: Unsplash

The HS2 Programme and the Secondary Specification Pipeline

Old Oak Common is one station in a programme that extends to Birmingham Curzon Street, Birmingham Interchange, and the stations of Phase 2 that planning reform and the 10-Year Infrastructure Strategy are progressively advancing. Each station in the HS2 network faces the same underground or partially underground environment, the same 50-year design life, and the same combination of humidity, cleaning chemistry, high-voltage traction power, and heavy passenger footfall that defines the underground rail secondary infrastructure specification requirement.

The HS2 programme, at an estimated £65 billion for Phase 1 alone, is the largest single infrastructure investment in UK history. The secondary infrastructure of its stations, maintenance depots, and operational facilities represents a small fraction of that total capital cost but a disproportionately large fraction of the lifetime operational maintenance cost if specified incorrectly. A peer-reviewed lifecycle cost analysis found approximately 50% lifecycle cost savings for GFRP versus steel over long study periods, driven by the elimination of corrosion-related maintenance (Younis, Ebead and Judd, 2018). Across the 50-year operational life of an HS2 station in the underground environment of Old Oak Common, that maintenance cost differential is a substantial and entirely avoidable operational expenditure.

Beyond HS2, the UK's rail infrastructure investment pipeline includes the Elizabeth line's ongoing maintenance and upgrade programme, Network Rail's Control Period 7 investment in station and track infrastructure, and the Transpennine Route Upgrade now in active construction across Yorkshire and Lancashire. Each of these programmes involves underground or partially enclosed station environments where the FRP secondary infrastructure specification case applies with the same consistency as it does at Old Oak Common.

The Moment the Platforms Go In Is the Moment the Specification Matters

The installation of the first passenger platforms at Old Oak Common marks the transition from the civil groundworks phase, where the primary structure of concrete and steel determines the form of the underground station, to the fit-out phase where the secondary infrastructure that passengers and maintenance personnel will interact with for 50 years is specified, procured, and installed. The platform slab installation that is happening now creates the surfaces on which secondary grating, cable management, signage, and drainage will be built. The specification decisions for those secondary systems are being made at exactly this stage of the programme.

Getting those specifications right now, in the engineering and procurement phase that follows platform installation, is significantly more effective than revising them after installation, when change is expensive, disruptive, and subject to the contractual constraints of an active construction programme. The secondary infrastructure of Old Oak Common will be in place when the station opens between 2029 and 2033, and will serve 250,000 daily passengers for the 50 years that follow. The specification decisions being made in the current engineering phase will determine whether that secondary infrastructure requires maintenance intervention before 2079. FRP does not.

Old Oak Common's first platforms are in the ground. The secondary infrastructure specification decisions that will determine 50 years of operational performance are being made now. Underground humidity, aggressive cleaning chemistry, 25kV traction power proximity, and 250,000 daily passengers create the most demanding secondary infrastructure environment in UK construction. FRP grating, cable management, structural profiles, and drainage are the specification that meets every one of those demands simultaneously, across the full 50-year horizon that Britain's new high-speed railway is designed to deliver.

Reinforce Technology FRP Products for Rail and Underground Transit Infrastructure

Reinforce Technology supplies FRP grating, cable trays, structural profiles, and drainage channels for rail and underground transit infrastructure across the UK, including mainline and underground station applications. Available in polyester and vinyl ester resin systems with fire-retardant formulations tested to the fire performance classifications required for underground public transport applications. Non-conductive, non-magnetic, and corrosion-immune across 50-year operational design lives in the humidity, chemical cleaning, and high-voltage environments of UK underground railway stations.

Contact us to discuss your rail infrastructure project and the correct FRP specification for your specific underground station environment and operational horizon.

Final confirmation of suitability for any specific railway application, including fire performance classification requirements under the relevant railway fire safety standard and structural loading assessment, remains the responsibility of the appointed project engineer. Reinforce Technology provides technical guidance and material recommendations based on information supplied to us, but specification sign-off should always sit with the qualified professional responsible for the design.

References

Global Railway Review (2026) HS2 Installs First High-Speed Platforms at Old Oak Common in Major Construction Milestone. Available at: https://www.globalrailwayreview.com/hs2-installs-first-high-speed-platforms-at-old-oak-common-in-major-construction-milestone/354216.article [Accessed: 22 July 2026]. [1,960 pre-cast concrete slabs; six platforms as three island blocks; 400-metre HS2 trains; Balfour Beatty VINCI SYSTRA JV; Explore Manufacturing Worksop].

HS2 (2026) Old Oak Common Station. Available at: https://www.hs2.org.uk/building-hs2/stations/old-oak-common/ [Accessed: 22 July 2026]. [850-metre underground station box; six HS2 platforms; eight surface platforms for GWR, Elizabeth line and Heathrow Express; TBMs launched January 2026 toward Euston].

HS2 Media Centre (2025) Foundations Complete for HS2's Old Oak Common High Speed Station. Available at: https://mediacentre.hs2.org.uk/news/foundations-complete-for-hs2s-old-oak-common-high-speed-station [Accessed: 22 July 2026]. [76,000 cubic metres concrete; 17,000 tonnes reinforced steel; 45,000 sq/m base slab; 91 concrete pours; ECOPact low-carbon concrete].

IntechOpen (2022) 'Fibre-Reinforced Polymer (FRP) in Civil Engineering', in IntechOpen Engineering Series. Available at: https://www.intechopen.com/chapters/84203 [Accessed: 22 July 2026]. [Non-conductive and non-magnetic properties; 75% lighter than steel; corrosion-immune in persistent humidity; no maintenance requirements across operational life].

NACE International (2016) International Measures of Prevention, Application and Economics of Corrosion Technology (IMPACT). Houston, TX: NACE International. Available at: http://impact.nace.org/economic-impact.aspx [Accessed: 22 July 2026].

Railway News (2026) Old Oak Common: 2026 Construction Update and Route Map. Available at: https://railwaynews.net/old-oak-common-station-project-london-transport-hub-hs2.html [Accessed: 22 July 2026]. [14 platforms total; 250,000 daily passengers; BREEAM Outstanding; WSP and WilkinsonEyre design; 42nd Elizabeth line stop; 100+ destinations].

ScienceDirect (2025) 'Sustainable composites for metal replacement: Environmental assessment and material selection of fiber-reinforced polymer across industries', ScienceDirect, doi: 10.1016/S2667-3789(25)00051-3. Available at: https://www.sciencedirect.com/science/article/pii/S2667378925000513 [Accessed: 22 July 2026]. [Pultruded GFRP manufacturing emissions approximately 60 to 70% lower per tonne than primary steel, cradle-to-gate].

Younis, A., Ebead, U. and Judd, S. (2018) 'Life cycle cost analysis of structural concrete using seawater, recycled concrete aggregate, and GFRP reinforcement', Construction and Building Materials, 175, pp. 135-144. doi: 10.1016/j.conbuildmat.2018.04.183.