Extension unit of independent train control vehicular system for intercity railways

The invention discloses an extension unit of an independent train control vehicular system for intercity railways. The extension unit has the advantages that communication interfaces and relay interfaces are extended for an ATP (automatic train protect) system, the interfaces are used as information exchange channels connected respectively with the vehicular ATP system, a vehicular ATO (automatic train operation) system, an RTU (remote terminal unit) system and a train interface unit, and accordingly the vehicular ATP system, the vehicular ATO system, the RTU system and the train interface unit can be communicated with one another; the extension unit is of a double-2-vote-2 architecture, a communication unit 1 and communication unit 2 of the extension unit are in hot-backup redundant relationships with each other, one of the communication units in a standby state is switched to a primary state when the other communication unit fails, and accordingly the integral systems can continuously run; existing ATP and