[yanellena]

There are other benefits to this too. With an electronic lock you can display the state of the toilet to other passengers on digital signage screens onboard the train. You could do this with physical locks but it would likely be more costly.

[lucb1e]

Putting a simple contact sensor on the deep end of a mechanical lock (costs about as much as a button since it can be the same hardware, except it needs to neither be big nor have controllable lights around it) is more expensive than designing a whole bunch of electronic circuitry and state machines and figuring out the best text you can write to make (young and old) people understand the state machine?!

The doors are also slow as heck, both because they slide a large distance at the speed of a snail in a hairpin turn and because half the people don't get the system. I'd be surprised if these electronic systems merely halve a toilet's hourly capacity compared to it being fully mechanical besides that 10-pence "occupied" sensor in the frame/wall side of the lock