It's a regular-sized door. Like this. No different. Except that in the top half, there's a small glass panel for observation.
8 seconds sound clip from the Odds Against Tomorrow (1959) movie soundboard.
You can hear this line at 00:55:52.111 in the Blu-ray version of the movie.
Quote context
[...]
- He called me. He insulted me. He was a very smart-talking character, and then he called me.
- He dared me. Like you are now.
- He comes out of the drugstore, and he crosses over with the light.
- Then he goes down the side street to the side door of the bank.
- I want you to meet Johnny Ingram.
- Sorry I'm a little late, but I had girlie trouble.
[...]