There are automated announcements for when lines are not operating. Also there are announcements for if the lift is not working at a station. I do not know if these announcements are completely automated from remote monitoring the lifts, or if the system has to be manually told that the lift isn't working. The way of testing this would be to open up a lift and disable it (put it on inspection) and see how long it takes for the trains to start saying that there is no step free access. I might try this, but it would be quite risky doing this.

http://beno.org.uk