Train Derailment in New York

Addressing whether the pusher will contribute to accident severity:

The mass of the locomotive may be substantially higher that those of the cars; but so is the force normal to the rail which allows for greater braking force.

The braking force will be limited by the static coefficient of steel on steel.

The braking system component variables such as - diameter of brake cylinder - length of lever arms - and composition of the brake shoes are optimized to operate in such a manner that the friction forces will be close to but not exceed those that would cause the wheels to "slide" which would increase braking distance and flatten the wheels.

Even with that said - the location of the prime mover and initial point of derailment or initial braking force would be important variables in the dynamics of the derailment; especially in a curve.

An emergency brake application is a bad thing - even on straight rail with well distributed mass and braking forces.

It is far too soon to jump to any accurate conclusions in this tragedy. The only thing that laymen should keep in mind at this hour is that four people are dead and eleven are in critical condition. My condolences and prayers go out to the friends and families effected by this tragedy.

Now to wander down the voyeur world of wild speculation.

Without knowing the very critical details of all of the safety systems, protocols and operational status of this train and track, I have always wondered about a train being pushed by an engine instead of pulled. If you pull a dragged chain along a flat surface, one link after another will self align without any guiding force from the surface. Pushing a drag chain requires all of the links to either be in perfect alignment or for the surface forces to impose some alignment on the links.

Pushing a train of cars requires the track to impose an alignment on these cars. Once a derailment happens, I would expect the type of folding action seen in the aftermath of this tragedy. However, by having the locomotive at the rear of the train still on the track the primary braking contacts still existed with the rails. This maybe why the lead car did not enter the river.

Last month at this same area of the tracks a freight train derailed. This will certainly provide detailed documentation of the nominal conditions of the tracks.

There are many facets both engineering and business related of this tragedy that need to be weighed by well skilled people with plenty of time and patience to mull over all of the facts.

Hitting a bend doing 82 mph on a section of track zoned at 30 mph might just be the leading cause for this wreck. That'd be my guess.

http://www.washingtonpost.com/business/nyc-train-derailment-kills-4-hurts-more-than-60/2013/12/01/fb8e3a0e-5ae8-11e3-801f-1f90bf692c9b_story.html

Criminal!

This guy should spend the rest of his life in jail.

lyn-

Don't jump to conclusions. This guy may have a slim chance for a good excuse but not readily confirmable. Stranger things have happened in railroad operations. Yes, as it looks now he was at fault but time will tell. Wait until the MTA, FDNY and especially the NTSB makes their report in over a year from now.

It seems too complicated to make a positive judgment at this time.

If anyone is interested, there is a lot of interesting reading at the NTSB.GOV web site. It also gives a very good reason for their investigations and cause determinations. They handle aviation, railroads, highway, pipeline, Haz Mat, Marine, among other things. They have accident reports for almost every major incident.

Remember the security guard at the Atlanta Olympics who was first blamed for the explosion and then they realized he was a hero?

Good Luck, Old Salt

old salt,

I gave him the benefit of the doubt, until I read,

"The driver, William Rockefeller, 46, wasn't paying attention, based on statements he made to interviewers moments after the incident"

"traveling 82 miles per hour on a 30-mph curve"

"straightaway leading to the curve had a 70 mph speed limit"

"train's event-data recorders showed the trains throttle going to idle six seconds before the engine came to a halt; maximum braking five seconds before the engine came to a halt"

"The brakes had worked properly at nine station stops after it left Poughkeepsie"

It's no jump at all.

lyn-

I didn't hear those releases. My position has now changed to one more similar to yours.

Good Luck, Old Salt

Today the human being should be a monitor - not an operator. That capability is decades old.

Politics and unions keep safety advances from being installed, there are driver monitors that sense when a driver is nodding off available in automobiles, and pilots need to be paying attention and override when computer approaches go awry. Peoples lax attitudes cause problems. Litigation, insurance solve nothing for the dead.

I think the problem is V squared over R.

"I think the problem is V squared over R." - And whether the L/V threshold was reached before the gauge went wide or the rail rolled over.

PHOTOS: Metro-North engineer minutes after crash