You have to be careful about terminology because it can vary between what you are talking about.

For instance, railroad signal systems use "stick circuits". But locomotives also use similar circuits regardless if you call them stick or latching circuits, but they also can use mechanical latching relays. On locomotives, best example of a latching circuit is the FPCR (Fuel Pump Control Relay). First energized by starting or priming, it creates its own feed to the coil through its normally open contacts. Pushing any one of the EFCO (Emergency Fuel Cutoff Buttons) interrupts the latching circuit and causes it to drop out (turning off the fuel pump and shutting down the governor). A latching relay is different, as a mechanical latch holds the relay in the picked up position. Best example is the ground relay that that must be mechanically reset (old EMD and GE 70 ton) or a reset coil energized (newer type). I just had to deal with a situation where a governor shutdown on a B23-7 caused a latching relay to prevent trying to restart it. It was one of the newer small Vapor relays with a not so obvious mechanical push button to allow it to drop out and reset. The Dash-2 and SS annunciator modules have a latching circuit in them to preserve their alarm indications until reset.

I don't recall ever seeing a mechanical latching relay in signal use and can't think where you would need or want to use one.

I do recall a couple of simple crossings that used an interlocking relay. If I remember, both had an island circuit added with its own common track relay. I think the ICC/FRA must have changed the requirements to require the island circuits.