A train will be considered to have a train control apparatus failure(failed train)when any component of the train control apparatus fails to operate as intended, such as:
1) the audible indicator fails to sound when required or continues sounding when not required.
2) the speedometer is inoperative, reading 0 mph when the train is moving or there is a constant no motion (v zero) indication
3) it is necessary to operate the cut out switch for the cab signals, ATC, ATS, or any other component of the train control apparatus, except when necessary for operation in MBS territory.
4) damage or fault occurs to any part of the train control apparatus.
5) the train experiences continuous cab signal flips.
6) when the train receives a cab signal indication( other than flip) that is not in conformity with fixed signal indication or other observable track occupancy or track conditions.