Third Rail Isolation Demonstration Project
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CTA utilizes an exposed third rail system to provide power to trains on all revenue and non-revenue tracks. The third rail is typically installed on insulator chairs spaced eight feet apart just outside one of the running rails. CTA's rail cars utilize a “gravity shoe” to collect 600 Volts DC from the top surface of the third rail. In station areas, the third rail is typically located on the opposite side of the track from the station platform – this provides some level of protection from a person falling off the platform and coming in contact with the electrified third rail. Unfortunately, there are incidences when a passenger falls off the platform with sufficient momentum to reach the far side of the track and make contact with the third rail. This proposed project will add additional safety features on the third rail in the vicinity of station platforms.
Funding will provide for two technologies: the Third Rail Isolation System and the Third Rail Side Guards (sideboards).
The first feature is a safety feature proposed to include the isolation of the third rail through the stations such that when no train is approaching or present at the station, the third rail would be de-energized. This additional feature would include a control device to energize the third rail in the station, and by-pass cables to carry current around the station to feed the third rail outside the station.
The second feature would include non-conductive side boards on both sides of the third rail which would reduce the likelihood of a person making contact with the rail. The sideboards would also provide an opportunity to apply warning labels directly on the third rail so as to better direct passengers to the hazard posed by this element. The sideboards would also provide a layer of protection for CTA employees that are required to walk alongside the third rail during maintenance activities.