Tommy Meehan wrote:In a derailment don't cars always wind up jack-knifed?
I don't know if they always do, but as others have mentioned, and I've seen photos, lots of jacknifes happen even when the locomotive leads. And beanbag mentioned that maybe the trailing locomotive here breaking the drawbar might have prevented a couple of the rear cars from sliding into cars in front of them.
Tommy Meehan wrote:The irony is, people like that are usually much more reserved in making judgements based on rudimentary evidence.
I'm sure not trying to say I have the answers, I just have the questions.
Tommy Meehan wrote:The railroaders say when a push/pull train goes into emergency a pneumatic valve cuts power to the locomotive. That's an air valve. That's sounds like a pretty basic system. It's the same thing when people were writing that the cab car sends a signal to the locomotive to activate the brakes. That's baloney.
No, it's not baloney. It is a signal in the basic physical science sense. Reducing the brake pipe pressure TELLS or SIGNALS the brakes to apply, because sufficient pressure in the pipe keeps the brakes released. As I said before, it doesn't matter if it's a pneumatic signal, smoke signal, carrier pigeon or dixie cups and strings: doing something at one end causes something to happen at the other end.
Tommy Meehan wrote:The cab car has a brake handle. When the engineer moves the handle it opens a valve that releases air from the brake line. When the engineer opens the brake handle in a cab car you can hear the air escaping. This isn't rocket science.
But if there's some obstruction in the brake line isn't it possible that when the engineer moves the handle that the part of the line after the obstruction might not get its air released, or at least might release more slowly than the part of the line before the obstruction? Isn't it possible that the longer that brake line is, and the more connections it has, the more possibilities there are for the line to have a clog? That's why I'm interested in hearing if the train had any problems stopping at any of the prior stations.
Tommy Meehan wrote:It's also possible if the locomotive was leading the locomotive might've stopped faster than the lead coach and then the cars behind would pile up. People died that way in Chatsworth.
That's one reason why folks like me wonder IF push is worse than pull, not that we KNOW one of them's safer than the other.