Assuming it’s fairly standard AHBC, it would probably get quarterly visits from a Level Crossing Manager, and an annual inspection, as well as some generic maintenance at some point.
The annual checks take a few hours and are done overnight, needing published road closures with associated diversions, and line blockages to access treadles and cabinets, as well as a couple of teams on the ground to actually do the tests.
So not factoring in any spare parts or proactive renewals I guess we’re already in the region of £100k