For arguments sake it seems a few folks have assumed the break apart was in a location that allowed the front part of the train to pull forward enough to clear the crossing under discussion.
Say your facing north on the street, the front of the train is pointed east or moving from your left to right…now lets say the break was on the west or left side of the crossing, then yes, clearing the crossing would be a matter of the conductor walking back, closing the inglenook, pumping the air up, and having the engineer pull ahead enough to clear, you wouldn’t even need a brake test considering the situation.
But what if the pull apart was on the right or east side of the crossing?
Pulling ahead would solve nothing.
And we have no real knowledge of what really broke.
Was it a knuckle, or did the coupler fail?
If it was a knuckle, then the swap out would be pretty much as described as above, have the hogger toss off the right knuckle, drag yourself up to that point, throw the knuckle on the rear crossover platform and shove back to the break, drop the old broken knuckle out and replace, about a 30 to 45 minute job…but if it was a coupler that failed, then nothing the train crew could do in repairs.
So now we are at the “have another locomotive couple into the rear of the train and drag it back” part…well, most railroads don’t have locomotives just sitting around, crewed and ready to spring into action.
If they were to have another locomotive cut away from their train, and come up against the rear of the broken train, then that crew would first have to tie down their train, assuming it was in a position and location to safely do so, then travel whatever distance required to reach the rear of the disabled train, couple into it and pump up the air…all of this would have to be considered after the reason for the break apart was determined, and then set in motion, so your looking at best case time wise, 30 to 45 minutes for a broken knuckle, one to two