Prioritizing Third-Rail: Why Aging Systems Are the Next Big Transit Risk
Guest blog by Steven Halbert, Transit Business Development Manager at Conductix-Wampfler (MHI member)
Trying something new feels both challenging and risky for established organizations. Too often, organizations and companies rely on the familiar, sacrificing long-term gains for short-term comfort.
Today’s transit authorities are no stranger to these trade-offs when it comes to the third-rail that powers subways and commuter trains across North America.
Understanding Third-Rail
Historically, when subways were first electrified, transit authorities utilizing conductor rail relied on a “third” steel rail to power their operations. But that third-rail was heavy and not very conductive. And, with increasingly power-hungry vehicles, the industry moved to a “composite rail” which consisted of a steel rail with aluminum bars bolted to the web.
But a third style of rail that is more conductive, easier to handle, procured in smaller lot sizes, and provides a smoother running surface for the collector paddle, began to make its mark globally in the late 1980’s and early 1990’s. This newer rail is made entirely of electrical-grade aluminum and capped with a stainless-steel running surface. And this rail is now the preferred solution globally.
However, the North American market has been reluctant to adopt this technology, embracing instead a “good enough” approach to their third-rail systems for the past 40 years. By taking this approach, North America has pigeon-holed itself into working with products that are less conductive, heavier, more difficult to maintain, and increasingly harder to procure.
So, let’s take a deeper look at why now is the time to switch to a better solution, and how the alternative stainless-steel-capped-aluminum power delivery (CAPD) rail supports system uptime and longevity, enhances safety, promotes sustainability, and ultimately keeps transit customers moving forward.
What Makes CAPD Third-Rail a Smarter Solution?
The Federal Transit Administration (FTA) reported that transit use increased by more than 17% nationwide from 2022 to 2023, indicating an uptick in ridership and a greater reliance on public transportation systems. Additionally, of the nearly 3,500 miles of third-rail in North America, just over 2,000 miles of it was installed before the turn of the century, meaning that just over half of North American third-rail is over 25 years old.
By analyzing your current infrastructure, you can determine if there are opportunities to modernize and integrate alternative systems. The CAPD third-rail system provides several advantages that can help future-proof transit systems:
1. Enhanced Conductivity Meets Energy Efficiency: CAPD third-rail systems comprise a solid block of aluminum with a stainless-steel cap, providing enhanced conductivity and durability. Compared to full-steel systems, the aluminum component increases energy efficiency, improving power transfer and supporting regenerative braking. Not to mention, transit agencies can meet sustainability goals due to CAPD rail’s energy-efficient aluminum-based solution, alongside the ability to rework the cap and save the aluminum when it is time for renewal.
2. Performance Longevity: The stainless-steel cap on CAPD third-rail systems supports equipment longevity. Carbon steel running surfaces have a far weaker electrical bond structure than stainless steel; thus, they wear at a much faster rate, which creates uneven running surfaces for the collector paddle. The uneven surfaces cause the collector paddle to “bounce” and lose contact with the rail, which, in turn, draws an electrical arc and further erodes the running surface. Adopting a CAPD third-rail technology system-wide can significantly decrease downtime for repairs and maintenance. This ultimately supports significant lifecycle cost improvements, including maintenance, safety, and energy, which outweigh the initial upfront investment.
3. Scalable Procurement: When installing new equipment, planned downtime is required. Most steel-only and composite rail systems must be procured in large quantities. This requires additional storage requirements and longer planned downtimes. CAPD third-rail systems can be procured and installed in smaller lot sizes, making them ideal for phased upgrades. The lighter weight of aluminum also supports ease of installation with less heavy equipment necessary to move the rail. Generally, the same profile in aluminum is half the weight of its composite equivalent and a third of the weight of steel. Transit authorities using CAPD third-rail can get their operations back up and running more quickly than with traditional third-rail systems.
4. Future Savings: Once CAPD third-rail is an acceptable solution within a transit authority, the increased conductivity and reduced electrical resistance can work into calculations for extensions and new lines. Using these new electrical calculation values, transit authorities may even be able to save the cost of a substation on future projects.
Armed with the knowledge that CAPD third-rail systems are a smart and efficient transit solution, authorities should begin to phase out worn, aged systems that will only require more time, effort, and resources for repair. Aging third-rail systems may seem “good enough” today, but they risk larger consequences tomorrow.
Taking the Next Steps
Now is the time to assess your current infrastructure and determine where upgrades are needed. Look for inefficiencies, recurring maintenance issues, and operational slowdowns that cost more than you realize. Those might be good areas to target a test for a CAPD third-rail system.
While any system investment can feel like a leap, start with a phased approach. Upgrading to scalable, more resilient, energy-efficient options, like CAPD third-rail, helps avoid operational pitfalls while positioning your organization for long-term success.
