CTA to Upgrade Signal System from Forest Park to Jefferson Park on the Blue Line

November 9, 2005
11/9/05

The Chicago Transit Board approved a $172.8 million contract at its monthly meeting today to upgrade to a cab signal system on the Blue Line from the Forest Park terminal to Jefferson Park on the O'Hare branch. The signal project also includes the installation of a signal system to connect the Red and Blue Line subways at the new transit station to be built at 108 N. State Street.

The new system will enhance CTA's ability to improve train movements by allowing trains to operate at continuous speeds. As a result, customers will experience smoother train rides and improved travel times. In addition, traction power cables that deliver power to trains will also be replaced resulting in improved reliability of service. The signal upgrade will also help reduce labor costs as fewer personnel will be needed during single track operation for maintenance or disruptions along the 20 miles of elevated, surface and subway tracks. The new system will also enhance communications between CTA's Control Center and field personnel.

The existing signal system along the 20 miles of track included in the project is an automatic block system that was state-of-the-art more than 50 years ago when the line was built. The system provides traffic lights along the tracks that tell train operators to proceed, slow down or stop. Traffic signs are also provided to give the operator information regarding track conditions and speed limits. The system also includes a tripping mechanism that will automatically stop a train that passes a stop signal.The new system will be a cab signal system that will provide more detailed operational information to the rail operator through electronic displays on a monitor in the cab. Information includes current speed allowance and actual train speed. This information is transmitted electronically to the trains from the track.

The new system also enforces maximum speeds. If a train's speed exceeds the allowable speed, an audible alarm sounds to alert the operator to reduce speed. If the speed is not reduced within 1.5 seconds, the train will automatically brake to a penalty stop.

The contract was awarded to Aldridge-Mass a Joint Venture. Funding for the signal upgrade project contract will come from the Federal Transit Administration (FTA) and the Regional Transportation Authority (RTA). Work is expected to begin in early 2006.

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