How about the old black and white film "Oh, Mr Porter" with Will Hay?
First time I saw that I was in tears of laughter! I'll have to dig out the vid and have another look!
Well I'm only 16 and I've got that on a video and I've also seen the Titfield Thunderbolt several times, which I just love! I've also seen Thomas and the Magic Railroad, no offence to any Americans here, but I think they have made an originally British idea into a rather American influenced one. Not that I like Thomas or anything
But I have to say that my favourite all time would be The Titfield Thunderbolt closely followed by Oh! Mr Porter!