Hmmm ... I can trace delays due to lion, sheep, cows, horses, puma, badger and deer. Have I missed any?
I was once held up on an
HST▸ approaching Reading by a pigeon that had flown through an open window, as the train was moving, and was in the vestibule between First Class carriages. We'd come to a halt anyway (we were approaching Reading after all...) and they'd obviously decided to get rid of the fare-dodger before pulling into the station.
TM‡ announced the reason for the extended pause with a tone to his voice that was somewhere between sheer annoyance and mild humour.