Analysis of Train Derailment in East Palestine, Ohio, from Stefan Jovanovich

Starts at Minute 4:00: A Failed Defect Detector and the Train Derailment at East Palestine

The achievement of railroads is that they can carry massive loads thousands of miles with an economic efficiency that no other form of ground transport can come close to matching. To do this they have to violate the first rule of all practical mechanical engineering and have metal scrape against metal without any lubrication. The wheels and rails are steel against steel. If an air brake fails for a wheel, it stops it dead and the wheel becomes a giant flint throwing sparks and then flames. The only solution to this problem is to slow the train to walking speed and move it to a siding. If the train continues at speed (30-40 mph in developed areas), that car will eventually derail. The unanswered question for this incident is why the train crashed in the pattern of an emergency stop by the engine, not the derailment of a single car. That could have been caused by the engineer not having the skill and temperament required to avoid literally slamming on the brakes because "the train is on fire". But, that is pure speculation by those of us sitting safe in the bleachers.

Bud Conrad writes:

Thank you for the explanation in bigger picture context. There seems to be something much more unusual about this particular incident, than just a mechanical failure, of a type that must happen frequently because steel is riding on steel.

Jeffery Rollert comments:

Modern rail cars have systems that brake all cars at once (locomotives included). It’s done by a radio signal or wire, and no longer a pneumatic propagation. I know, because a very good friend designed and built the system decades ago. Cars derail, when the locomotive derails and effectively becomes the brake. So why did the locomotive derail?

I haven’t seen the video, but strongly suspect something in the tracks or a switch was improperly diverted that the locomotive couldn’t handle the redirection at that speed.

Henry Gifford explains:

Steel rolling on steel is a great idea because there is such a small amount of friction. An adult human can allegedly push a fully loaded (200,000 Pounds or more) railroad car along a level track (but not get it started – another story). Rubber covered wheels, in contrast, require much more energy because heat is generated as the rubber flexes (internal friction from molecules rubbing on each other). But, if the railroad train car bearings seize up, steel is sliding on steel – still lower friction than rubber rubbing on a road, thus the locomotive(s) can drag it along until derailment.

If/when a train car derails, the rubber air hoses connecting one car to the other – in a long chain the length of the train – break, which lets the air out of the braking system along the whole length of the train, as if the brakes were put into emergency stop.

The air brake system in use today was designed and patented by George Westinghouse to be “fail safe” in the sense that a failure stops the train, instead of a failure allowing the train to keep going, maybe going too fast on a downhill…. However, trains these days are longer than George probably imagined, thus it takes a while for all the air to bleed out of the system at the locomotive end, leading to a situation where the brakes are fully applied at one end of the train and not applied at all at the other end. Because of this, trains routinely slow down in advance of anticipated stops, which reduces overall speed along the route. And, if the train slows below a certain speed, it must stop completely and wait until the air bleeds out of the system along the whole length of the train before starting again. They still get where they are going, but more slowly than they would with a better system.

The solution is to use electronic means to apply the brakes simultaneously along the entire train, which would improve safety while avoiding otherwise unnecessary slowing or stopping caused by limitations in the air brake technology in use today. The challenge is to maintain compatibility between all the freight railcars in the US fleet. While today not all railcars are compatible with all tracks (weight, height, width), the whole fleet is compatible in terms of connectors between railcars, the wheel/track fit, etc. The brakes are (I think) all 100% compatible fleetwide, which has tremendous advantages.

The braking technology in use today is, at least in theory, compatible back to the original air brakes invented in the 1860s. In practical terms, I think there has never been a situation where some freight cars can’t be put on a train with other cars because of a lack of compatibility with the oldest cars in use anyplace in the country. Right now the industry is implementing an electronic system that will control the air brakes simultaneously along the length of a train. The new system is being introduced fleetwide with a minimum of compatibility problems going both backwards and forward; something the computer industry could take a clue from.

As for the hazards of transporting chemicals in tank cars, the federal government has, in recent years, repeatedly increased the required safety of tank cars. The tanks are required to be covered with thermal insulation that keeps the product from heating up quickly in the case of a fire nearby. The required amount of insulation on new cars, at least for those that transport petroleum products, has been increased repeatedly. Other safety improvements have been added – most related to avoiding spilling of product in the case of an accident.

As discussed below, the recent incident seems to have been caused by a fairly routine bearing failure that was not detected in time. “Routine” in the sense that these failures occur rarely among the huge number of wheel bearings on a long train, and usually only occur after a number of miles that far exceeds the life of a typical automobile or truck. But, they still occur. Usually they are detected by sensors/cameras along the track that “see” infrared light (heat emissions on the infrared light spectrum – the way that about half the heat moved from sun to earth gets here) emitted from a hot bearing or hot (dragging) wheel, and report the same to the train operator by radio. The trackside “hot boxes” also report by radio to a train operator the news that there are no problems with a train, if that is the case, which means that parts of the hot box system are, in effect, tested each time a train passes.

What is apparently unusual about the recent incident is that a wheel was reportedly sliding along the tracks (the resulting shower of sparks was reportedly seen by a security camera) but was not detected by or reported by the next hot box. Or, maybe it was reported but the train operator did not slow the train in response.

Bo Keely adds:

It's a very old hobo trick to get a train to stop by disconnecting the brake hose under your feet. The train emergency stops and one must skedaddle before the front end brakeman walks the line to couple the break.

'Hot boxes' on RR wheels are so common that before a freight pulls out a yard a worker always walks or quads the line of cars looking for overheated wheel journals. It's also very common for a train I'm on to stop in the middle of nowhere due to a hot box and have that car sided before continuing. Hot boxes are the big chance for hobos to talk to workers to glean information on where the heck he's going.

Stefan Jovanovich comments:

JR is right about the propagation: the signal is no longer pneumatic but by electronic networking. But they are still "air brakes" in the sense that the pressure is exerted by gas pressure.

Bud Conrad writes:

…This criticism of lobbying money and discussion of company support now that it is public may interest some.

Henry Gifford asks:

Could this be the cause of all the supply chain problems in the US?

Bo Keely writes:

pulling a brake hose to emergency stop a train is an old but infrequently used hobo ruse. in all my rides i've only seen it happen twice and I wasn't the one who did it. but that's enough to encourage newcomers to sit at the back of any car to not be thrown off the front in a sudden stop such as a derailment.

Stefan Jovanovich offers some color:

RanOutOnARail

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