When Larry is drinking a mug of tea while talking to Pat in the Railway station office, at first his hand is around the mug then he holds the mug by the handle.
Shortly after the start of the film, a Southern Region (of British Railways) streamlined Bulleid pacific locomotive is seen on the express train passing the camera. Later, the train is stated to have stopped at Pickering, which was on the Eastern Region of British Railways, where such locomotives never ran in service. Rugby is also mentioned, which was also on the Eastern Region of British Railways. It is also clearly stated in the film that the train is on the way to Edinburgh, on the East Coast (Eastern Region) Main Line from London. Also, the junction station where the train stops and the main action takes place is fictional.
When the suspect is handcuffed to the parking brake handle and then released to be handcuffed to another man, behind on the wall can be seen a pressure gauge for the train's braking system. Both needles (one for the main train pipe and the other for the brake reservoir) are shown pointing at zero. This could not happen on a fast moving express passenger train. It would be impossible! If there's zero pressure in the system it would mean the train's brakes would not function! It would mean the carriage they are all in or its braking system isn't connected to the rest of the train or the train driver's brake brake control handle.