The Coming Revolution in US 3rd Rail Transit Systems

Aluminum Conductor Rail

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In the last 75 years, the majority of US 3rd rail transit systems were built using all-steel power rails.   While not electrically optimal, steel rail was easily available and provided good life. Electric power was abundant and inexpensive, making the inefficiencies of steel power rail tolerable.  Also, the cost to install heavy steel rails wasn’t much of an issue.  But now, the world’s 3rd rail transit operators are discovering the advantages of aluminum-stainless steel (AL/SS) 3rd rails.  European metro systems are moving to AL/SS and Asian operators have widely adopted it for new systems.  What has prompted the move to aluminum power rails?

In recent years, the shift in system operating costs has revived interest in aluminum versus steel power rail.  Aluminum has lower electrical resistance than steel, resulting in lower voltage drop and less power loss.  Aluminum rails are less than 1/3 the weight of steel rail making them easier to handle and install.  As the costs of electricity and labor rise so do the advantages of aluminum over steel.  In some cases, the lower voltage drop will allow  power substations to be located farther apart, thereby reducing the number required.  The lighter aluminum power rails can significantly reduce costs of rail transport, handling, and installation.

The relatively hard aluminum power rail will not, by itself, provide adequate system life.   However, adding a stainless steel "cap" to the aluminum rail body provides excellent wear and corrosion resistance while reducing electrical pitting on the rail surface.  The cap greatly increases the life of the rail, while retaining the electrical advantages of aluminum.  Early concerns about the long-term viability of AL/SS rails have been allayed by the proven performance of hundreds of miles of AL/SS rail operating in a variety of climates and conditions worldwide.

The field-proven and patented Welded Cap Rail AL/SS conductor from Conductix-Wampfler represents a radical improvement in the way AL/SS power rails are constructed.  This innovative design eliminates any potential for the cap to delaminate from the rail.   With WCR, 3rd rail system operators around the world can benefit from the "aluminum advantage" without any concerns about system integrity.

  • Securely welded around the body, so it can flex as the aluminum expands under thermal stress.  The cap cannot delaminate even under demanding conditions.
  • Welded on the edges away from the running surface, providing a smooth and consistent surface unmarred by welds or grinding.
  • Applied under pressure and electrically bonded to the conductor body with a layer of non-oxidizing conductive grease; eliminates the possibility of corrosion build-up between the cap and the rail.

Available in standard 3000 amp, 4500 amp and 6000 amp configurations.  Sepcial designs are possible.

Welded Cap Rail combines the conductivity and light weight of aluminum with the tough, consistent, and long-wearing features of stainless steel.  It handles more current and incurs less voltage drop than an all-steel rail.  This is the "green", energy-saving alternative to outmoded, corrosion-prone steel power rails.  Welded Cap Rail has proven superior to other capped aluminum rails on the market and has been tested and approved by NYCT.