This is an unusual image taken by a passenger on board one of the old freight cars being pulled by the C.K. Holliday. The "cattle cars" were not in use for long, and the open-topped cars seem mighty unsafe. It looks like everyone is standing, what happens when the brakes are applied?
I've had this slide for several years, but when I gave it another look this morning, I noticed the tent in the distance. The Mickey Mouse Club Circus tent! Now there's something you don't see in many photos. I am pretty sure that by the time this photo was taken, the Circus had closed (it opened Thanksgiving Day 1955, closed January 8th 1956), replaced by Professor Keller and his "Feline Fantastics".
Anyway, it's a pretty neat bit of obscure Disneyland history, I'm glad to have a photo of it!