Here in the UK the pendolino class trains, at least while operated by Virgin, were notorious for entering into an oscillating open/close loop. So much so that s

Here in the UK the pendolino class trains, at least while operated by Virgin, were notorious for entering into an oscillating open/close loop. So much so that several times the staff would announce which cars had working toilets after each pickup station. Often times, apologising for the smell in the other cars.