In the Leyland Atlanteans in Sydney (they are Leyland PDR1A/1s
and not AN68/2Rs) they have a counter which ticks over everytime
someone goes up or down the stairs. They have never failed, ebcause
it uses no electronic devices, just a spring which is connected up
to a counter, on 2 consecutive steps.
I have managed to stuff up a counter on the VSO...go up the stairs,
then leap down two stairs, then climb up again, the leap down, and
go up... quite funny 