Railroad car coupler question

[Abilene Slim SASS 81783]

I’ve been binging on westerns lately and many have scenes where someone disconnects one or more cars of a moving train by easily removing a pin. Wouldn’t that be dang near impossible since the couplers are under so much tension from pulling the car?

[Cold Lake Kid, SASS # 51474]

Better ask Pat Riot.

He'd know.

[Pat Riot]

Uh...Yep! Pure hogwash. 

[Trailrider #896]

Yup, pure Hollyweird!  Even when the train was stopped and the brakeman went between the cars to "pull the pin", he might either get crushed or lose a hand or finger(s) if not careful...and lucky!  The only way you could pull the pin with the train moving would be if it was going downhill and the trailing cars had run the slack out.  And, if the movie is about pre-1900 or so, there wouldn't be any Janney (knuckle) couplers, as they weren't required until around 1901, and some branchline outfits might not have had them then!  Even with knuckle couplers, with tension on them, it would be much harder to pull the lifting rods.

[Perro Del Diablo]

@patriot knows how to fall off now he just needs to learn how to land

[twelve mile REB]

The couplers shown in most westerns are not the couplers used 1840's to 1880's (link and Pin). That being said it all has to do with slack.  If the coupler is under tension pulling the car or train then the pin quite probably could not be lifted at least not by hand.  However if the coupler is not under tension or very little tension, car or train being pushed then yes the pin can be lifted quite easily.