We’ve almost all seen pictures of train derailments. Engines and cars thrown about willy-nilly, as if slapped sideways by some rather nasty-minded giant.
Luckily, most derailments do not end in tragedy or death. In fact, a good number of derailments only result in the train coming off the tracks and staying upright, and not crashing down on its side. That was the case with the recent Union Pacific train derailment in Houston, near Harrisburg Boulevard and Hughes Street. The locomotive and six rail cars of plastics went off the track, but remained upright, causing no injuries.
However, in other cases, the accidents are nothing short of spectacular – and devastating. This year alone (2015) there have been four cargo train derailments in the Northeast, rupturing tank cars, spilling oil, polluting waterways and starting enormous fires that burned for days.
But what causes these train derailments in the first place?
Contrary to what you may think, it usually isn’t the proverbial distracted or sleeping engineer at the controls.
- Rail Defects. The number one cause of train derailments is broken rails and welds. Logical, because if the rail the wheel is riding on is defective, the train will follow that defect and jump the tracks. Over 15% of train derailments are caused by these broken rails and welds.
- Track geometry is another significant factor. If a curve is too tight, or a grade too steep, a train’s massive momentum will make it move in a straight line, and jump the tracks. 7.3% of train derailments happen because of less than optimal track geometry.
- Buckled tracks (many time due to extremely high summer temperatures which can literally warp the steel rails), broken train wheels, wheel bearing defects and failures and axel defects account for another 18% of all derailments. In fact, very cold weather can also be a problem. In the Northeast especially, frigid temperatures can make steel rails and steel wheels more brittle – causing derailment accidents.
All in all, 46.7 percent of derailments are caused by various track and wheel defects while 28.7 percent are human error factors, such as excessive speed or braking miscalculations. The remaining 25% can be chalked up to switching errors, improper train and track maintenance and train on train accidents.
Train derailments caused in part by human error are often due to excessive speed around a curve. Just the diesel locomotive alone can weigh from 100 to 200 tons. Each car behind the locomotive can run from 22 tons (empty flatbeds) to 143 tons fully loaded.
- Since a train’s momentum is inversely proportional to its speed, a train travelling at 100 mph will have 16 times the effective mass than one going at a leisurely 25 mph. That’s a lot of momentum to contain when making a sharp curve!
- An average freight train moving at 55 miles an hour requires at least a mile to stop after emergency brakes are fully applied. An eight-car passenger train moving at 80 mph needs about the same distance – a mile. Any error in judgement can be a costly one.
- Rock ‘n’ Roll. One cause of train derailments happily on the decrease due to better engineering is what‘s known as a “Rock ‘n’ Roll” derailment.
This strange phenomenon happens when a freight train is travelling between 12 and 24 miles an hour. A harmonic motion interacts between the train and the tracks, causing the cars to sway back and forth – often in a rather violent fashion.
What is the Magic Behind 4 feet 8 ½ inches?
Standard rail spacing in the USA is 4 feet 8 ½ inches in length. When you think about it, this is a rather odd number to come up with. So was there a method behind this madness?
Rail spacing in the States was determined by rail spacing in England. English engineers handled the first railways here, so they used what they had been using in Merry Old England.
Why did the English use this odd number? Because pre-rail transportation (carts, wagons and such) had wheels set at 56 ½ inches apart. Which now begs the question – why were those wheels so built?
The answer was because they had to fit in existing wheel ruts cut into the roadways from years of use. If the wheel spacing were of a different size, they could easily be damaged when hauling merchandise.
But why were those original ruts cut at this odd size? Blame that on the Romans, who liked to standardize most everything. That was the spacing most used for their chariots and wagons.
OK… now for the $64,000 question: Why did the Romans choose 4 feet 8 ½ inches?
That was the optimal length to fit a wagon or chariot behind the rumps of two horses.
So you may say our modern railroads owe their particular flavor to a stallion’s behind.
Strange… but true.
TRAIN – VEHICLE COLLISIONS
When a train hits a car or even a truck, it is no contest. The vehicle will lose 100% of the time. It is very rare for such a collision to derail a train though it has happened.
The normal sequence of events is that the vehicle is either crushed and smashed out of the way or dragged along the tracks until the train can stop. Either way, any passengers in the hapless vehicle are usually immediate candidates for the morgue.
So please, if you think your car or truck can outrun a moving locomotive at a railway track crossing – don’t bet on it. It may well be the last wager you will ever lose.
TRAIN TRAVEL IS SAFE
There is only one modern mode of transportation safer than train travel – commercial airliners. Here are the statistics:
Overall Deaths per Billion Miles Travelled – 2000 through 2009
- Motorcycles: 213
- Cars: 7.3
- Ferries: 3.2
- Trains: 0.43
- Commercial Airliners: 0.07
TERRY BRYANT LAW FIRM
Terry Bryant Law Firm in Houston has been helping Texas residents for 30 years with their accident-related legal problems and concerns. If you or a family member have been injured in a train-related accident, Terry Bryant will help you get all the assistance and legal aid you are entitled.