What is the incremental probability that a 200-car freight train will derail compared to a 120-car train?
What is the incremental probability that a 200-car freight train will break down enroute compared to a 120-car train?
BNSF has a locomotive service facility at Temple, TX. Locomotives being serviced are frequently moved into or out of the service sheds and from one track to another within the service areas. On occasion, they run on the main to the yard north of the city or to the fueling area south of the city. The distances are approximately 3/4ths of a mile and two miles. Would the engineers moving the locos on the main be fully qualified engineers or would they have a restricted qualification?
Statistics wasn’t one of my strong classes in college…
As for equipment moves, very likely hostlers, as opposed to regular engineers. They’ll be familiar with the local plant, perhaps moreso than a road engineer.
You might get a first approximation by taking the MTTF from something like M-942 and ASSuming that any particular bearing might be the ‘next to fail’. Count the number of bearings on the cars and apply the relative likelihood.
On the other hand, that’s a spurious metric. There is nothing about a 200-car train that makes bearing failure more likely, so if you calculate the percentage of failure for the number of bearings moving in 24 hours you’d get the same result, just as you would if you moved the traffic in shorter, but more frequent, moves.
To get a bit more involved, you could calculate the additional risk of a nominal accordioning pileup occurring after a catastrophic wheelset failure on the xth bearing or wheelset of a long train – this would be related to train speed and the number of cars after each sampled x in the train. A simplified version would be to take a ‘window’ of cars and move it forward and backward in the consist (lessening in intensity as you get to the back end). But note that the peak damage remails 40 cars…
A wreck like the one at Panhandle, where the isolated DPs shove the rest of the cars into the pileup at 40+ mph, though, and all bets are off.
Additional variables to consider for the derailment probability calculation:
Longer trains will tend to produce higher in-train and train-track forces.
How differently does the engineer operate the longer train compared to the shorter one?
Does either train have one or more DP remotes? DP speeds up air brake applications and releases and can help manage slack.
I’d like to see a citation for this, and how much it may have contributed to the size of the wreck. The DP consist should have stopped pushing the instant it received an emergency braking signal, either by radio when the lead unit went into emergency or pneumatically after the brake pipe was severed as a result of the crash.
I expect it depends on where the yard limits are. If, for some reason, the yard limits encompass those other places, and it’s only a light engine move, then I expect a hostler (restricted qualification) would be allowed to do it.
Yard limits can be as big or as small as the carrier wants to make them to accomplish their purposes. The carrier can change Yard Limits whenever they find it necessary.
The article about the SP Siskiyou Line in the April issue of Trains (came today) notes that the yard limits in the Belleview (?) area ran from MP 451.6 to MP 425.5…
My guess is that you’ll find no formal citation, or current online reference. I know about it from seeing the first posted cellphone video, before it was taken down ‘minutes later’, showing cars rolling at speed into the growing wreck, not slowing down at all. It was and is one of the most horrifying things I’ve seen.
Apparently the head end impacted so hard that the radio was destroyed, and the DP considered it a typical LOS and ran the timer down.
CSX named a segment of track in Baltimore Terminal after me as a Yard Limit. By designating a Yard Limit on that particular segment of track it then allowed MofW track authority to be issued on the track segment.
Yard Limits can be created for many different reasons.
Yard limits don’t matter in this discussion. It’s a type of main track authority. Switching limits, a contractual boundry between road and yard work defines a terminal area.
Most likely the hostlers moving the locomotives outside of the service area have class 1 Engineer’s licenses. They would have at least a class 2 Servicing Engineer’s license. A-k-a, a hostler’s license.
There’s two kind of hostlers, at least there used to be. Inside hostlers only move locomotives around the engine/shop facility. Outside hostlers moved the power to/from the engine facility to the yards and/or trains within the terminal.
Most outside hostler positions have faded away with the changes in work rules over the years, with PSR doing away with most of those that were left. Inside hostlers now are almost sure to be mechanical dept. people. Any place that would still have outside hostlers would almost always use fully licensed engineers.
At one time, firemen who couldn’t hold any other assignments could go hostling, if the railroad felt they were qualified, this being way before the Federal licensing requirements. Back then, engine service and train/yard service were separate career paths. If you couldn’t hold any engine service jobs, you were furloughed. Now, those in engine service start out in train/yard service first. If they can’t hold an engineer’s job they can flow back to train/yard service. Different railroads have different rules regarding flow back.
Years ago, before I went to engine service, I held an RCO license working the remotes in Des Moines. (My current certification still shows RCO qualification but I haven’t operated the remote box in 20 years. I still have my RCO vest in my locker.) At the time it was debated by those in charge to give us a little more training to qualify us as Servicing Engineers. This so we could move eng
Trains April 2023 pg 6. Present COO of CN is interviewed by Bill Stephens “……….One of the first things he noticed was that CN wasn’t sticking to it’s operating plan. “”It was as simple as running on time. From that we looked at train length. We were running trains way too long, way out of slot, which created a lot of havoc across the network and really killed our service offering””……””So we got trains back where they need to be……velocity jumps up 10%””………(Stephens)….unplanned recrews and deadheads went down, and service improved. (Harris)””We stay with the schedule seven days a week and we run the same schedule every day. If the traffic’s there, we are going. If the traffic’s not there, we’re going. Whether it’s 120 cars or 40 cars, we’re leaving on time.”””
Very interesting read. endmrw0310232051