11. All Metro-North and Long Island Rail Road trains have cab signals , as do some New Jersey Transit trains. 12. At no point can the ATC system override the maximum speed limit enforced by the cab signal system. 13. Occasionally, cab signals are used by themselves, but more commonly they are used to supplement signals placed at lineside. 14. It and the former Conrail properties are the only CSX lines to have cab signal requirements on their entire system. 15. Modern CDUs on passenger trains are often integrated with the speedometer, as cab signals now serve a speed control function. 16. Over time the PRR installed cab signals over much of its eastern system from Pittsburgh to Philadelphia, New York to Washington. 17. The rebuild will also include the installation of locomotive speed limiter ( LSL ), and cab signals and other electronics upgrades. 18. Then, the train's speed must be further reduced to no more than within 70 seconds of the initial cab signal drop. 19. Pulse code cab signals work by sending metered pulses along an existing AC track circuit operating at some chosen carrier frequency. 20. In more advanced versions, cab signals are linked to automated controls that slow or stop a train if it violates signals.
