NJT HOBOKEN TERMINAL ACCIDENT THREAD

The MU cable does not tell the locomotive to brake, the brake pipe does. I've only had 1 electronic brake stand fail on me and the train went into emergency immediately so that is what i am going to assume would happen if the same occurred here but you never know.

Cab cars do not have air bags.

But if the brake pipe is not in the equation for service braking since it is all electronic between the cars, how does the locomotive know to brake? Also, doesn't the locomotive blend in dynamic too?

EP brakes use an electronic signal first to tell the brakes to apply, the brake pipe is pretty much the backup means. This is why those of you with scanners hear the Acela's doing 2 brake tests, the first you check the EP braking and the second you are checking to make sure you still have brake pipe integrity in case the EP fails. The brake pipe is always in play.

A minute ago, it was said that the brake stand is electronic with no air release until emergency. That would imply that the brake pipe is remaining fully charged in the release state, with the braking on the cars being managed entirely by EP until the handle is in emergency, then the air dumps. So are you saying that the brake pipe is being reduced at the same time as the EP controls for service braking? If that's the case, how do the cars know which to trust... EP or the brake pipe? Or do the cars just totally ignore the brake pipe until it is dumped into emergency?

BandA wrote: sensor(s) malfunction putting the microcontroller in an invalid state where it "freezes" and won't adjust the brakes and continues to tell the engine that the MU cable is connected so the engine doesn't brake.?

Yeah, unless the thing's designed by an absolute moron, the watchdog timer should reset the micro after a few miliseconds of the micro being in la la land, and then the initialization code should start by basically dumping all outputs, which should dump the air. There's probably a good amount of back-checking that goes on in the system that'd catch an issue long before it got that far.

In any case, why didn't he just pull the e brake cord, or for that matter, what the hell was the conductor up to that he didn't?

MCL1981 wrote:A minute ago, it was said that the brake stand is electronic with no air release until emergency. That would imply that the brake pipe is remaining fully charged in the release state, with the braking on the cars being managed entirely by EP until the handle is in emergency, then the air dumps. So are you saying that the brake pipe is being reduced at the same time as the EP controls for service braking? If that's the case, how do the cars know which to trust... EP or the brake pipe? Or do the cars just totally ignore the brake pipe until it is dumped into emergency?

Here's a good EP brake explanation. I met the brake pipe is always in play because it's still always connected and there in case the EP fails.

http://www.railway-technical.com/ep-brakes.shtml" onclick="window.open(this.href);return false;

That also says the brake pipe basically stays charged in the release state during service braking with EP doing all the work. The air only being dumped in emergency. So wouldn't the locomotive's brakes have to be getting their cues from the EP system as well? And presumably it does it's own thing with blending air and dynamic braking?

Nasadowsk wrote:In any case, why didn't he just pull the e brake cord, or for that matter, what the hell was the conductor up to that he didn't?

As the train was pulling into Hoboken, I would imagine that the aisles were jammed with commuters taking their stuff down from the overhead racks and ganging up at the vestibule doors, preventing a crew member from reaching the emergency valve. That's what happened on the Federal in 1953 when an angle cock worked itself closed between (I think) the 2nd and 3rd cars, making the brakes inoperative on the rest of the train. If a crew member had pulled the air rearward of that point, the brakes on that part of the train would have gone into emergency, but no one could reach an emergency valve because the aisles were blocked.

From,various news sources,passengers on that train are now planning to sue NJT over the wreck.
Figure on the Power and cab car on that set will be on legal hold after NTSB releases them.

Probably the whole thing. I doubt the cab car will see service again given the state of the roof.

pumpers wrote:

Head-end View wrote:Yes, the evening news tonight said the manufacturer found that the locomotive recorder was not working; period. How's that for a kick in the head? Let's hope they have better luck with the cab-car's recorder when they can finally access it.

On nj.com a NTSB guy was quoted saying that legally a recorder is only required in the lead car - the cab car in this case. But I assume then that when the engine was leading on recent trips there was no working leading event recorder -- another violation for NJT I suppose - I wonder how often they are supposed to check them?
They also said the recorder in the engine was from 1995, and the cab car recorder was a newer model from the 2000's.

The federal regulations allow the recorder to be placed elsewhere so long as the required parameters of the lead locomotive are recorded. So it may not have been required in the locomotive.

jackintosh11 wrote:Probably the whole thing. I doubt the cab car will see service again given the state of the roof.

My guess is the cab car is stripped of anything salvageable and scrapped. Parts might be used to get 6001 back in service after hitting the paint truck at a crossing.

A lot of misinformation, and misunderstanding regarding air brake being thrown around in this thread.

EM2000 wrote:A lot of misinformation, and misunderstanding regarding air brake being thrown around in this thread.

That's very helpful. Thanks.

As soon as I saw Computer Controlled Braking mentioned I had a nagging feeling that it was going to play a big role here. I think we have become far too reliant on computers for some critical tasks. The poor old CNJ did just fine with their homemade push pull sets; 1920s coaches, with plain bearings, Sharon 5 by 5 shank couplers, 24 or 26 air on the locomotives, etc. Not a computer in the lot. I remember reading, perhaps in Trains mag years ago, a quote from an engineer that basically said that if he made a a brake application, he wanted his hand on a valve that was connected to a piece of pipe that did something directly. He didn't want to rely on a bunch of transistors on circuit boards to control his air for him. Yes, I'm an old-timer, but enough said-