What happens when a locomotive seperates from its train ???

some one asked this question in a round about way recently . I.e if a coupler or drawgear breaks , what happens ??
It seems the brakes would come on when the air hoses part . then its a question of what slows down first .
Anyone know ?

The (now-)front of the train will slow down first, because the air from the last car has to go all the way along the train out the parted air hose. I speculate that the electronic braking assist has a fail-safe so when it loses its signal from the motive power, it applies the brakes (dumps air locally).

Similar effect for the other section of the train, only back to front.

On the locomotive the engineer will bail of the brakes and keep the front end moving, to make sure the rear of train won't hit the power.

Theres alot of variables there David, i ripped my train in half quite a few times last year. I'm gonna send you and Russ a PM.

Anyone else want it? PM me and ill sent it to you also.

Thanks for the info .
Here in Nz , they use this method to test the brakes on rebuilt passenger cars .
I believe what they do is run the train up to track speed , with the carriage under test been the last carriage . they then shut the air valves off between that carriage and the rest of the train , then uncouple it , and acclerate the train away . as the air hoses part , they drop a marker on the track , and measure the distance from that point to when the carriage comes to a rest . you then have the emergcency braking distance of that carriage alone , without having to fiqure out the effect of the rest of the train on it .
but then , theyre working on a budget you probably wouldnt even bother converting into US dollars !

We work like that sometimes also, but not at high speeds, slick way of cutting the cars off in the yard. Cutting them off on the fly. Just have to make sure you have enough room to keep moving forward with the power so they dont end up hitting you. I've heard some good stories about guys going to fast, doing it too close to switches not being lined for them, cars end up hitting them, or they get hit and end up getting shoved threw the switch, or they just run it to avoid the impact.

geuss it all comes down to experience , though i would say some never get the knack .
sounds abit like riding a motorbike fast on a windy road . either you learn to do everything smoothly at the right time , or you end up in the poo .

Think most of that was due to hurrying. I can remember a time or two when i was a brakemen, when my hog tryed to slam us, without me saying anything, when it looked like we were in the clear, id grab the angle cock and the pin, eather when the cars started setting up threw the vent, or the hog giving her a little more power, it would pop, ya could tell the hoghead started to freak a bit and slow down as the cars are fallowing us. Get on the radio real quick "Keep going keep going... gotter on the fly."

I was on a train a couple days ago when the knuckle on the lead end of the fourth car back gave way. We were going around a curve at the top of the hill, our three Dash-9,s moving 125 cars at little more than a walk, and the next thing you know is the power surged ahead. I looked back and saw a nice car length size gap open up between the third and fourth car in the consist. And the engineer swearing and hearing a lot of air being bailled. What I didnt know was why did the GE's shut down after things came to a stop?

What I didnt know was why did the GE's shut down after things came to a stop?

The PCS there buddy. It lets you stay in power (the motors still load) just a short time to out run the cut coming at you. I think its something like 30 seconds.

Im sure a long time ago there was plenty of hogheads who kept trying to pull on the train long after the air went, dragging cars on the ground alot longer then he should have. That PCS is a safety thing.

can you override it ? I'd imagine , if you had a string of tankcars full of fuel derailing , you'd want to get as far way as possible ?

Nope you cant.

That would be a good explanation. It would also explain why the engineer was a bit miffed, when his power died