Joe --
Having personally cut locomotives off of trains before, when the car inspectors were too lazy to venture out of the bunk room when I was in a hurry, I can say for a fact that a 5 minute engine change is not only possible, but could be done ever quicker. Shutting down the 480 requires pushing only one button in the cab of the locomotive. 6 cables must be unpulged from the locomotive, three on each side, and two valves closed. Thats all. All that takes about, maybe two minutes, if only one man is doing it. Then you cut off the engine, put the other one in, plug in the cables, open the valves, push a button to put the 480 up, and do a on and off brake test. Good to go.
We routinely change engines in 5-10 minutes in Hoboken, when we know in advance that it will need to be done. You need to have the replacement locomotive ready and in position, but aside from that, its a quick move.
Now, if they were to change the engine in Suffern, as you suggested, who would bring over the new engine? There are other crews on duty in Suffern, but they might already be on a train waiting to depart behind the express. Also, what locomotive would you use? If you take one off a train, how will that train make it in? Unfortunatly, because your train was still able to move, at a reduced speed, your train took the hit. A train was going to be delayed or cancelled because of this, no doubt as there are no spare locomotives laying around the railroad. Sorry.
Proven Theory #2 - If you don't work for the railroad, you don't know more than the people who do, no matter how many years you've hung around the tracks, or how well you think you understand railroading.
Rest in peace Jtgshu.