Incremental train control system

A train control system employs a series of wayside control units spaced along the track, each of which has responsibility for the control of trains in a corresponding local area and monitors track availability and signal status in its local area. Each wayside unit has a data base in memory that comprises fixed data defining an operational profile of the associated local area, and is provided with a data radio for transmitting profile messages containing the fixed data for that area and authority messages containing the dynamic data bearing track availability and signal status information. A data radio in a receive mode on a train receives the data transmissions from the wayside unit or units responsible for its control, and an on-board computer determines the proper train control instructions from the received data. A central control facility may also be provided for storage of master fixed data files that cover the entire route, relevant portions thereof being downloaded to respective wayside units via dispatcher data lines and updated periodically as necessary.