Route control system for railroad interlockings

Remote control apparatus for routing trains through a railroad interlocking which includes a plurality of locations marking the boundary limits of the interlocking track layout at which trains enter or exit the interlocking, track circuits for detecting train occupancy of predetermined track sections within the boundary limits, and control and indication means at the track wayside for track switches which establish individual routes, comprising in combination,

• a. a selection means associated with each limit location and operable in pairs for sequentially selecting the entrance and exit locations of a desired track route,
• b. a registry means coupled to each selection means and responsive to operation of that selection means for registering the selection of that location as an entrance or exit for a desired route,
• c. primary means responsive to the selection of an exit location subsequent to an entrance location for locking out conflicting routes and all other possible exit locations and connected for holding a registered exit location stored,
• d. an exit storage means for each location coupled for checking the non-occupancy of the track sections between the selected entrance location and the corresponding location when it is a possible exit and controlled by said primary means for retaining the exit storage only when that location is selected,
• e. a separate selection means for each alternate route between any two locations in said interlocking layout,
• f. a separate registry means controlled by each alternate route selection means for registering the selection of the corresponding alternate route in lieu of the basic route,
• g. an auxiliary storage means associated with each alternate route selection means and controlled by said primary means and the registry means associated with each limit location of the corresponding basic route for storing the final establishment of any route, alternate or basic, between the associated limit locations,
• 1. each auxiliary storage means coupled for inhibiting the registration of the corresponding alternate route selection if the associated basic route is already established, and
• h. secondary means for each location controlled by said primary means and by said track circuits in accordance with track occupancy conditions and coupled to the corresponding registry means for holding the entrance selection registered while the route is established,
• 1. each secondary means responsive to occupancy of the last track section in an established route for cancelling the entrance registry storage to release the established route,
• i. each registry means further coupled for cascading the cancellation of a route entrance storage to release the associated exit selection registry and the corresponding exit storage,
• j. the pair of registry means for each limit location of each possible basic track route through said interlocking, any associated separate registry means for an alternate route, and the associated exit storage means coupled for jointly actuating said track switch control means to complete the corresponding track route when entrance and exit selections for that route or an associated alternate route are registered and stored.