Exclusive interview with Lee Gregory, Director - Third Rail Solutions at REHAU

Lee Gregory is a seasoned track engineer with experience and education in civil engineering and project management. He has engineered the installation of hundreds of miles of railway track, including high-profile projects, in the United Kingdom and Singapore. His expertise focuses on enhancing track quality, reliability, and safety, significantly contributing to the efficiency of rail networks in these regions. Since 2013 he has managed high-performing international teams in the design, manufacture and delivery of third rail systems. 

Currently, Lee serves as the Director of Third Rail Solutions at REHAU. In this role, his intent is to implement best practices in third-rail technology across the globe. His focus is that REHAU continues to deliver state-of-the-art solutions that meet the evolving demands of modern urban transit safety and performance. 

Could you provide an overview of the third rail system and its main applications in rail and metro networks?

The third rail system is a widely used method of supplying electrical power to trains, particularly in urban rail networks such as metros, subways, monorails, and automated people movers. It uses an electrified rail, installed either alongside or between the running tracks, to transmit power to the train via a collector shoe in continuous contact during operation. Older systems often relied on legacy materials like full steel rails and steel supports, which are now considered obsolete. Modern designs, such as those recommended by REHAU, use full composite Alu-Steel rails and GRP supports, offering significant improvements in safety, lifespan, maintenance, and therefore life-cycle costs. These state-of-the-art materials enhance reliability and reduce long-term costs, making the third rail system ideal for high-density transport in space-constrained environments.

What are the primary benefits of using a third rail system, and what types of projects or settings make it most advantageous?

The third rail system offers significant advantages over catenary and rigid overhead systems, making it a preferred choice for many urban transit scenarios. Its compact design reduces the need for the extensive infrastructure required by overhead wires, leading to savings in tunnelling, construction, and maintenance costs. This design is particularly beneficial in tunnels, confined spaces, and densely populated urban areas. Additionally, its unobtrusive nature preserves the visual appeal of cityscapes, seamlessly blending into surrounding structures without the clutter of overhead systems. Maintenance demands are also lower, as third rail systems feature fewer moving parts compared to overhead wire setups.

These attributes make third rail systems ideal for urban transit networks where space is limited, aesthetics are a priority, and moderate-speed operations suffice. Metropolitan areas with extensive underground routes, such as metro and subway systems, benefit most from this efficient and visually integrated solution. 

From your perspective, what challenges are associated with third rail systems, particularly regarding maintenance, safety, and durability?

While third rail systems are efficient and well-suited to urban transit, they require intelligent design considerations to mitigate safety risks. The exposed electrified rail can pose a risk of electrocution, but with REHAU’s fully insulated GRP supports, a well-engineered cover system, and robust safety protocols, the risk is significantly minimized. In fact, incidents involving third rail injuries are extremely rare, as the system is typically confined within a protected zone, ensuring safety for both workers and the public. A high-quality cover system also shields the rail from adverse weather, preventing disruptions from rain, snow, or ice.

Durability, a common issue in older steel rail systems, has been significantly enhanced in modern designs. Legacy systems suffered from wear due to constant friction between the collector shoe and the rail, requiring frequent repairs and replacements. In contrast to lower-quality third rail options from other suppliers, REHAU’s stainless steel rails are expertly engineered with an optimal combination of higher grades of aluminium and steel. This ensures high electrical conductivity alongside an exceptionally durable wearing surface. Rigorous testing confirms that these rails are built to last over 100 years under normal operating conditions, delivering unparalleled longevity and reliability.

These advancements, paired with robust maintenance strategies and modern materials like GRP supports, enhance the system's safety, durability, and cost efficiency, ensuring it remains a highly effective solution for urban transit networks.

How do third rail systems differ from overhead electrification systems in terms of design, installation, and operational efficiency?

Third rail systems and overhead electrification systems differ significantly in design, installation, and operational efficiency. Third rail systems use an electrified rail positioned at ground level, while overhead systems rely on wires suspended above the tracks, accessed by pantographs mounted on trains. These design differences impact installation: third rail systems require precise insulation, protective barriers, and a confined setup, while overhead systems necessitate poles, suspension structures, and sufficient clearance for wires, adding complexity and cost.

For higher speed urban and intercity routes, the overhead catenary system is a more suitable for providing power to the trains. Conversely, third rail systems are optimised for compact urban transit, where their lower power requirements match the needs of moderate-speed, short-distance travel. Third rail systems also integrate seamlessly into confined spaces, such as tunnels, and provide aesthetic advantages by avoiding the visual impact of overhead infrastructure, making them ideal for dense urban environments.

In your opinion, is the third rail system more eco-friendly than overhead electrification? If so, could you elaborate on how it supports sustainable urban transit?

The third rail system can be considered more eco-friendly in specific urban transit contexts, particularly for compact systems like Automated People Movers (APMs) and monorails. Its streamlined design requires significantly fewer materials for installation compared to the poles, wires, and extensive support structures of overhead electrification, resulting in a lower environmental footprint during construction. Its unobtrusive structure also preserves existing urban landscapes and optimises land use, seamlessly integrating into dense cityscapes. Moreover, REHAU enhances this sustainability by incorporating a high proportion of renewable energy in the production of its components.

When coupled with renewable energy sources, third rail systems further support low-carbon operations. They enable energy-efficient technologies like regenerative braking, which recovers and reuses energy during operation, reducing overall consumption and emissions. For cities prioritising sustainable growth and green transportation initiatives, the third rail system offers a practical, environmentally conscious solution for modern rail networks.

What future developments or advancements do you see for third rail technology within the rail and metro sectors?

The future of third rail technology is driven by innovations that enhance safety, efficiency, and sustainability. Advanced materials, including high-strength alloys and durable composites, are being developed to improve conductivity and mechanical properties, significantly reducing wear and maintenance demands. Higher voltage systems, such as 1500V DC, are gaining traction due to their improved efficiency. REHAU’s GRP supports, already rated for this voltage, are well-suited to meet these demands and should be a key consideration for future metro designs alongside other advanced safety features. Additionally, the implementation of a fourth rail system, as successfully deployed by REHAU in Kuala Lumpur, offers a cost-effective solution for the negative return current, lowering operating expenses and simplifying trackform construction.

Modern monitoring technologies, such as IoT-enabled systems, will further advance the industry by providing real-time data on wear, overheating, and electrical faults, enabling predictive maintenance and minimising operational disruptions. Energy optimisation remains a crucial area of progress, with the integration of storage technologies like supercapacitors and batteries allowing for the capture and reuse of regenerative braking energy. REHAU's systems in the UK, which facilitate battery charging for trains, exemplify this trend toward energy-efficient solutions.

These advancements, aligned with increasing priorities on sustainability and urban transit growth, position third rail technology as a cornerstone in the evolution of efficient, cost-effective, and eco-friendly rail and metro systems.

Urban Infra Group is hosting the 5th RailTrans Expo in June 2025 in New Delhi. Will REHAU be participating in the event to showcase and promote its new innovations/technology in third rail systems?

We are highly interested in showcasing REHAU's systems at the 5th RailTrans Expo in June 2025. At this stage, our participation is under consideration as we evaluate how best to align our strategic initiatives with opportunities in India. We recognise the importance of displaying our innovations and engaging with industry leaders, and we will share updates regarding our plans in due course.

Anything else you want to share with our readers?

The third rail system combines innovation and practicality, enabling cities to build efficient, reliable rail networks tailored to urban needs. As sustainable transportation becomes a priority, REHAU leads the way with advanced solutions like Alu-Steel rails, GRP supports, polymer cover systems, and energy-efficient technologies such as train battery charging and fourth rail systems. Designed for durability, safety, and sustainability, third rail systems offer unmatched performance, blending seamlessly into modern urban landscapes.