Well, this trail's closed, sir.
4 seconds sound clip from the Battle Circus (1953) movie soundboard.
You can hear this line at 01:22:42 in the Blu-ray version of the movie.
Quote context
[...]
- Sergeant, tell them to get out of there but quick!
- Mash 66.
- Let me have that map... Heading for this area here.
- Well, this trail's closed, sir.
- How long will it take you to get them out of here?
- Well, they're dug in pretty good, sir. The terrain's on their side.
- Maybe a couple hours, maybe a couple days.
[...]