Interlocking - Defined Forms of Locking

Defined Forms of Locking

Electric locking

"The combination of one or more electric locks and controlling circuits by means of which levers in an interlocking machine, or switches or other devices operated in connection with signalling and interlocking, are secured against operation under certain conditions."

Section locking

"Electric locking effective while a train occupies a given section of a route and adapted to prevent manipulation of levers that would endanger the train while it is within that section."

Route locking

"Electric locking taking effect when a train passes a signal and adapted to prevent manipulation of levers that would endanger the train while it is within the limits of the route entered."

Sectional route locking

"Route locking so arranged that a train, in clearing each section of the route, releases the locking affecting that section."

Approach locking

"Electric locking effective while a train is approaching a signal that has been set for it to proceed and adapted to prevent manipulation of levers or devices that would endanger that train."

Stick locking

"Electric locking taking effect upon the setting of a signal for a train to proceed, released by a passing train, and adapted to prevent manipulation of levers that would endanger an approaching train."

Indication locking

"Electric locking adapted to prevent any manipulation of levers that would bring about an unsafe condition in case a signal, switch, or other operated device fails to make a movement corresponding with that of the operating lever; or adapted directly to prevent the operation of one device in case another device, to be operated first, fails to make the required movement."

Check locking or traffic locking

"Electric locking that enforces cooperation between the Operators at two adjacent plants in such a manner that prevents opposing signals governing the same track from being set to proceed at the same time. In addition, after a signal has been cleared and accepted by a train, check locking prevents an opposing signal at the adjacent interlocking plant from being cleared until the train has passed through that plant."