A push-to-make switch is a push-button type of switch that doesn't lock into place when pressed, it allows power to connect through a circuit temporarily for as long as it is pressed in, the circuit is only complete for as long as the switch is held in position, after which the circuit returns to an isolated state. The most common use for this type of switch is a doorbell or the bell on a bus.
In railway modelling we use push-to-make switches to release a burst of stored energy from a CDU (Capacitor Discharge Unit) to operate point motors and for the operation of semaphore signals.