A friend and I were involved in a similar incident in Scotland during the early part of 1983. It was on a Sunday morning when trains from Glasgow Queen Street to Edinburgh and the North were being diverted via Cumbernauld and we were travelling in the leading vehicle (Mark 1 TSO no. SC4903) of the 09 35 Glasgow-Aberdeen. A couple of miles past Cumbernauld, we passed a Mark 2f/3 Edinburgh-Glasgow push-pull service and there was the most almighty crashing sound, accompanied by glass flying everywhere. A very large and heavy open mark 3 door had hit the side of our carriage. We were the only passengers in that vehicle, sitting on the right hand side, and were extremely fortunate in that the open door, smashed the first two windows - and their aluminium frames - before flying back against its own carriage as it passed the third and fourth windows where we were sitting. It then returned for another bash, taking out windows 5 to 8 and causing considerably damage to the second vehicle - a mark 2 BFK - before being wrenched off its hinges and falling into the six foot. On coming to an emergency stop, the guard examined the damage, transferred us to the third coach and locked-up the two affected vehicles, which had also had all their off-side door handles taken off as well as bodywork and window damage. On arrival at Stirling about half an hour late, where we were alighting, the two damaged vehicles were removed to a siding and the train continued about 40 late.