First of all, Thank God for this fact, whatever the reason!
Nevertheless I always wondered, if one goes to RailPictures.net and looks at the derailments section there are lots of freight train derailments throught the times but hardly any passenger ones (unless there was an accident at grade crossing). Which makes me wonder: passenger trains have the same or even higher speeds they go on the same rails, have same metal wheels, pretty much the same truck construction. How come they don’t derail as much?
Consider how many fewer passenger trains there are versus how many freights there are, multiply by the difference between the number of freight cars versus the number of passenger cars, multiply the result by the expected cost of the resulting derailment if passengers are involved and you can see why passenger train derailments are rare.
Passenger cars are designed differently for one and the weight distribution in the cars is pretty static compared to a freight car that can have a varible distribution, add to the fact that they don’t run as often as freight and you’ll see why.
As noted above, it is largely a factor of the number of trains. Another issue would be the size of the trains. Passenger trains are usually short and freight trains can be very long and this makes for different handling qualities.
Inspection tend to be a little fussier, too – and much of the equipment is newer (believe it or not…). Also they tend to be found on better-maintained track (no insult, guys – again a function of the smallo number of trains)
Perhaps somebody can cite the number of derailments per train mile traveled for passenger trains versus the same measurement for freight trains in the U.S.?
Here are my theories: First, Pasenger trains-generally-run only on well-maintained main lines. They are less likely to be on diferred maintence yard tracks, sidings or branches. Second: There is someone that can stop the train in at least one of every four cars in a passenger train. So, a problem can be reported to the head end. A very high percentage of freights have operating people on the head end only, sometimes as much as a mile to two miles from the rear of the train. A marker can only tell you so much no matter how sophisticated it is. If there is a problem with a passenger car, some one might notice a problem in time and the train can be stopped before there is a derailment. On a freight,however, the only way the crew might know something has gone wrong is when a car has derailed. Talking defect detectors are regarded as luxuries, found only on high density main lines, or if a federal/state subsidy can help with the cost anywhere else. Otherwise, some one trackside or on another train may see something, but if your train is the only one around for hundreds of miles–there you are. Even when there were more employees around, simple vigilance didn’t always prevent derailments. In a few cases they were part of the reason the derailment occurred!
Interesting info, PBenham!
But I always thought once the car wheels jumped the track, that’s it. In a split second it derails and even if engineer knew what can he do besides applying emergency brakes and by then it’ll be too late. On model railroads train can go quite a distance with one car off the track but in real life this will simply destroy the truck.
Anyway even if engineer knew the second wheel jumped the track what can he possibly do?
…How about another thought…The slack in the coupler system in comparson…Passenger system has minimum and freight couplers a much higher bracket of slack…and in braking, especially emergency possibly that has an effect…How about it railroaders, does the tight couplers of the passenger sysem help prevent derailing…?
First, I think you would have to find out if there really is a difference. As previously said, number of derailments per train mile would tell. Unfortunately, I don’t know how or where to find this info.
buddy, knock on wood![}:)][:D]
Just baised on the cost of each there is a night and day difference between freight and passenger trucks. They can only run at these speeds because they are engineered to. If you look at the trucks under Amtrak’s “freight” cars on the rear of there long distance trains you will see they are not the same as boxcars. There is a big difference between high speed and freight trucks. And inspite of the fact our congress says Amtrak has plenty of money for maintenence there shop guys do a great job. They know peoples live’s depend on them cause its not freight that will “hit the dirt”. [bow]
First, as has already been mentioned, sheer probability. Many more ton miles of freight than passengers. This would particularly be pertinent for mainline derailments at speed.
Second, again as has already been mentioned, the pax runs are generally on good track. A lot of freight moves at 40 mph or less, on track that’s limited to those speeds.
Third, passenger trains are not usually switched, particularly to the extent that freights are. With the exception of some terminal moves, most of the motion is forward, start and stop. The opportunities are just that many fewer for derailments as a result.
Plus all of the other factors that have been mentioned.
Houston Ed and Muddy Feathers will certainly have more input if they weigh in.
I think someone metioned slack, but what about the amount of weight being pulled by the coupler.
OK granted pax trains don’t derail that much, but then again could it be that some of the pax train derailments or wrecks be more/less destructive to the people inside?
Really you don’t need to dump me into a diesel flamer …
Having a wheel, truck, or even an entire car derail is not always an immediate disaster. Many times a derailed car can run on the ties for miles before it hits a switch or a road crossing that throws it out of line causing a pile up. Sometimes it will even rerail itself and no one knows of the derailment until another train or track inspector spots the chewed up ties, switch points, grade crossings etc.
one other factor is that passenger trains tend to have very uniform carlengths - that as well as uniform weight - tends to eliminate stringlining type derailments.
dd
Even in the real world of railroading, cars can have one or more pair of wheels derailed and they can be pulled several miles before either rerailing themselves or causing a catastrophic derailmentt.
I didn’t know that…
In that case why can’t every car have inexpensive device similar to bump sensor on our car alarms. If car starts shaking badly for longer time than just needed to pass through switch that’ll indicate wheels are running over ties. The device then can simply transmit alarm code uniquely identifying car (like active RFID tag) and engineer can initiate controlled braking. Even if this cut wrecks by 50% I think cost savings would be huge!
You can drag them for quite a while before they decide to actually bust the air line or derail and fall over.
If the car is equipped with shelf couplers, they can go miles with out a truck, supported only by the coupler on the next car.
As for the frequency of freight versus passenger derailments…well, it is sorta like saying, why are there more automobile accidents involving Chevys than Rolls Royce…the sheer number of chevys means the odds of an accident involving them instead of the Rolls is going to happen.
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Even back in the “golden age” of passenger service, the number of freight cars and freight trains outnumbered passenger by a large percent.
And, as has been pointed out, passenger equipment is built to different standards…no one cares if the bags of corn in the boxcar has a ride smooth enough to not spill a drink!
Freight cars take a much more severe pounding in switching service than passenger equipment.
You can not design freight equipment the way you do passenger cars, today, the boxcar might be hauling newsprint, tomorrow, bagged corn, the next day it might have bricks in it.
Passenger cars are purpose built/ designed to haul people only, so you can invest in the “better” trucks and suspension, as you are designing for a single purpose.
Hence, they can run at higher speeds than freight.
If you compared them on a percent of fleet basis, the numbers would not reflect a large difference.
But on a car to car, or on a sheer number basis, there flat out is so many more freight trains out there than passenger that there is no way the numbers could even be close.
Ed
Excelent question.
In basic terms…
More frieght trains…
More derailments.
Less passenger trains…
Less derailments.
But what your saying is that if there was any pictures of passenger train accidents, the person who took it must have ran off.
A true railfan would watch and see if everyone is alright and still alive.
But when the newspaper reporter comes, they would ask you if you have any photos?
Or, if a officer asks if you have any evidence stating if it was the engineer’s fault or whoever or whatever caused it.
“Common Sense isn’t expensive.”
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