What causes trains to derail?

Question

What causes trains to derail?

Answer 1

1. Obstruction on the track. Even a small item like a pebble or a small piece of metal can derail a speeding train.

2. Going too fast around a sharp curve, or going around a curve too sharp for the train vehicles' wheelbase.

3. Collision with another train.

4. Faulty track, as in a recent accident in Britain when track had expanded and distorted in the heat. Broken rails are another possible cause.

5. Facing point (one where the tracks diverge in the direction of travel) changing underneath the train causing one or more carriages to jackknife - this is what happened at another recent rail accident in Britain.

6. 'Rough shunting' - doesn't happen much now, but in the days when lines of wagons were pushed into sidings and left to roll to the end, wagons could get derailed by being shunted too heavily.

7. Wheel fault - a wheel broke on a train in Germany a few years ago and this caused a train to derail.

8. Overshooting the end of the track - this is a potential accident at a terminus, but is very unlikely to happen as heavy-duty buffers will absorb most of the impact of a runaway train and bring it safely to a stop.

9. Trackbed subsidence. A danger present when there is flooding.

10. Another danger caused by flooding is bridge collapse - this happened in Wales about 20 years ago when a bridge went down in a flood, the train went into the water and several people were drowned.

11. Wheel slip when braking - due to slippery rail surface, the effects of gravity or both, a train fails to stop when the brakes are applied. Used to happen occasionally with loose-coupled goods trains but extremely rare now as all trains are continously braked.

Rest assured however, accidents like these are extremely rare and the railway is still a much safer form of transport than roads where accidents are happening all the time.

Answer 2

Unsafe speed, warped tracks, sabotaged tracks, large objects intentionally or unintentionally left on the tracks.

Answer 3

There many factors for derailment, mostly either human error of lack of maintains on the rail infrastructure.

Answer 4

There are many reasons, Human err,faulty equipment including track cars, weather conditions.

Answer 5

Train gets derail for many reason.

1. Impatient drivers try to cross the railroad crossing or lightrail crossing when train is about to come. Lightrail and trains has right way and they are metal, and if they crash, they derails.

2. Cajon Pass, California is very steep according to show about "Train Wreck." One of engineer brake, but brake got loose and it hit derail because there was no way to slow it down and it crash into neighborhood's house like tornado.

3. When train hit tanker, it create big explosion like many people think it looks like 9-11.

4. I don't remember where, in "Train Wreck, they sure that ferry in foggy and because it was foggy, ferry hit the Amtrak Bridge. Amtrak did not know ferry bridge was damage and when it hit the bridge, bridge gave away and Amtrak cars hit the river.

5. One of past motorman was speeding in NYC because he was operating train with DWI. He overshoot the subway stations from abandoned City Hall Station to 14th St-Union Sq.

As part of construction, he was suppose to switch to express track and when he hit, first two subway cars got hit and others got ready. It suspended subway service for 2 hours.

6. There was another incident in NYC. Not-in-service Amtrak going back to Washington, DC had rammed  onto Long Island Railroad's rear car which injured 127 people on East River Tunnel. In this case, Amtrak had human error. He was suppose to operate 15 mph. He was driving 10mph, however he had fail to stop.

Answer 6

usually this happen when rails are weaken by weather or lack of maintenance.

Answer 7

Trains derail when decars slip off detrack.

Answer 8

they crash duhhhhh

Answer 9

The two most frequent reason trains derail are hot wheel journals, commonly referred to as hotboxes, and broken rails or sun kinked rails. These are followed by the Engineer exceeding the speed for the gross tonnage he is pulling. In the event he must drop air in an emergency, this speed causes what is know as an accordion effect. The weight toward the rear of the consist continues its inertia forward like squeezing an accordion together. These are the real massive pile ups where cars can be stacked several stories high, and cause the most extensive damage.

Answer 10

Drugs, drinking and fornication my friend...

Answer 11

You have a number of very good responses:

I would add widening gauge caused by weak track, or sun kinks  too much speed where the track is rated for a 10 mph restrictions - a frog at a switch can put an engine on the ground if conditions are just right.  An engineer has to know the run and speed restrictions and track conditions.

  A broken rail or an improperly lined switch or large objects on the track, ( really large ) can do this.

Washouts, damaged bridges can happen.

Sometimes defective equipment, brakes that won't release can over heat a wheel and cause it to break.

It can be train handling, or human error can contribute.

Also even if going to full emergency only adds 20% more braking power ( this is not dynamic braking) , it can be a contributing factor.

An unlocked facing point switch could open under a train in movement - and before the rule here in the US was created,  occaisionally a crew person may become confused and line a switch incorrectly... that is why one stands on the other side of the track when a train is moving over a switch lined for its movement,  and in some cases over a hundred feet away ( two facing trains - one on a siding waiting for one on the main track to clear ) .

There are lots of reasons. Some are avoidable, a rare few are not.   Sometimes its due to trespassers who tamper with equipment.

Sometimes its caused by motorists,.especially  the ones who drive larger vehicles or trucks that don't wait for trains at crossings.

I often think of that first rule : When in doubt always take the safe course " .

Answer 12

There can be many factors.  Briefly, defective rails from lack of maintenance to weather related issues.  There could also be wheel issues from the locomotives and/or cars:  thin and/or high flanges, or flat spots on the wheels.  In addition, improper speeds due relative to track conditions or switches, to include switches in the wrong positions.

Answer 13

Rango nailed it.

The only thing I could add is to say train make-up itself can cause a derailment.

In heavy grade territory, where there is also usually to be found tight curvature, train make-up restrictions are in place to try to reduce the potential for a derailment.

As an example, where specified by timetable or general orders, certain cars cannot be coupled together, such as a very long car coupled to a very short car.  It may be that the head ten cars must weigh over 50 tons or short cars no closer to the engine than 10 cars, etc.

A lot of it would be avoided if some tonnage restrictions were mandated by law and forced upon the carriers.  The ECP brakes are a'comin'.  Without restrictions in place, say hello to 24,000 ton, three mile long trains.

Then sit back and watch the fireworks.........

Addendum:  It is too easy to banter numbers about.  Lets put it into perspective, 24,000 tons.

The largest naval destoyers of WWII were those of the Akizuki class of the Imperial Japanese navy, at 3,700 tons.  These were some big boats.  So, put six and a half of 'em on roller bearings, then put steel wheels with the roller bearings, then put the whole shooting match on steel rail where there is an extremely low coefficient of friction, then send the whole thing down a 2.5% grade (or more).  That's a 24,000 ton freight train.

Answer 14

There are many many reasons, literally hundreds.

Human error is NOT the main reason although unsafe train handling can and does cause derailments.

Broken couplers (drawbars) can drop down below a car and lever it off the track

I dont know the cuases broken down by number but based on expereince I would think track defects.

Rail gets horribly stressed and breaks under a train once in awhile. Tracks can buckle in the heat, called "thermal buckling" causing derailments.

Guage or distance between the rails is critical, if it gets even a couple inches out a car will drip through and cause a deramilment.

Snow and ice buildup in winter can cause a deraliment.

Floods, washouts, avalanches, mud and rockslides have all caused deraliments

Mechanical defects on rolling equipment such as axles, bearing or wheels can fail causing derailments

I can add dozens and dozens more causes but these few are probably the cause of most derailments.

It's odd if you contemplate this from the other side of the coin, think about this. . . .. . . the top of the rail is not as wide as the palm of your hand, the wheel flange is not much higher a nickel's width. The actual contact patch between a rail and wheel is about the size of a dime. How does any train ever stay ON the rail when you look at it that way??

I think about this when I start into a sharp curve with a two hundered foot drop straight down into the river sometimes on a cold stormy winter night LOL.

Answer 15

Rango and Hoghead have hit it on the nail.  People who are so anal that they "can't be bothered with waiting for a train" cross the tracks; get themselves painted over the front of the locomotive; that sometimes could cause a derailment.  Sometimes vandalism causes it.  Sometimes, it's nothing more than the rails get hot and bend out of alignment.  Believe me, even a 1/4 inch deviation in gauge will cause a derailment.  But if you're enjoying the breezes of the south Atlantic coast of this fair country -- the main cause of derailments is corporate greed -- they think of profits over safety.  Think bout this -- one railroad limits all their trains to 45 mph for "safety reasons".  That lessens the stress on the rails -- so they don't have to spend money repairing them.  BUT -- they let AMTRAK run 79 mph over the same track.  You can see it coming:  More people losing their life due to the lust of the almighty dollar.

Answer 16

well it depends on whose fault it is...

Answer 17

What causes a train to derail?

1. Wide gauge NYCTA  the gauge is 57 1/2" anything over that is asking for problems.

2. not observing the proper speed while riding over switch's.

3. spikes and other instruments that hold the plate to the tie that are left unmaintained and become loose therefore resulting in a wide gauge.

Answer 18

I agree with Hoghead except on tonnage.  I operate coal trains of 150-180 cars that easily exceed 26,000 tons with no problem.