Is an "emergency stop" the fatest way to stop a moving freight train?

Question

I guess when you "lock the brakes down" on a long train you are basically sliding metal on metal as the locked wheels skid down the track. Is it more effective though to have a controlled application of the brakes where the wheels do not lock (is this even possible in an emergency or are you required to hit the emergency stop)? When a lock up does occur, does it mean that all of the wheel sets on the train will experience some degree of damage due to flat spots?

Answer 1

right now it is. They were testing a new air brake system a few years back called eab electronic air brakes where each car was connected by an electric cabel so that when you made a brake application every car set up at the same time that was a sweet set up, but I don't think the rr's will have them installed untill they are forced to by the fra.

Answer 2

No, almost all train cars have a load/empty portioning valve and you will NOT slide the wheels. Sliding wheels even for a short distance will ruin the wheels almost instantly, flat spots of only 2 1/2" long render a wheel unusable.

Sliding the wheels does not stop a train very efficiently, I have been on a locomotive when the wheels started sliding and it almost felt  as if we were on greased rails.  Hollywood has it all wrong.

But there is a faster way to stop a train in certain circumstances, I have heard it called a "wildcat" stop, and I can promise you it works.

Coming into full dynamic braking, (if equipped) and going into full automatic brake application or dumping the train from the rear so the dynamic brakes stayed on full is faster.

The extra 10% of braking effort gained by emergency application is more than offset by having full dynamic brakes, especially at speeds of 30 mph or above.

Answer 3

Rango is close, but when a train goes into "emergency", it evacuates ALL the air out of the main train line.  A train car can not tell the difference between a load and load, it loses all its air regardless, which pops the piston on the brake cylinder all the way out. On a loaded rail car, the wheels WILL NOT slide, on an empty rail car, the wheels PROBABLY will NOT slide. The only way to get a wheel to slide on a car is to tie up the handbrake at the end of the car.  We slide cars around all the time when switching and such, we aren't really supposed to but it is so much faster during repeated switching then climbing up and tying handbrakes or untying handbrakes. Cars can slide for a long way before having to have the wheels turned (resurfaced) or replaced, if you live or have access to the railroad tracks, you can listen when a train goes by, and cars that havent been slid much will hum past rather quiet, and then you will hear a car clunking past you. this car has flat spots on the wheels. It can actually be extreme enough to make the car "bounce" off the rail at speed if the flat spots are bad enough. For this reason, we always observe trains passing us on the line of road for excessive flat spots, and other defects of course. Let me know if you need more information. Thanks

Answer 4

the best way to stop a train should there be an emergency is find a conductor if you do a dumb thing like that, you mite derail the train.

Answer 5

each wheel on a vehicle is equipped with brakes. the emergency cord triggers the entire brake system. of course skidding is unavoidable. that stands to reason considering the weight of both car and contents. as to damage or wear and tear, all of these criteria are considered in the design and manufacture.

Answer 6

Vehicles have implemented ABS to prevent lock ups. This is because vehicles travel in two dimensions and control is limited if not impossible if thw wheels where to lock

Trains are one dimensional in that they travel along a straight line. To answer youre question, No, it would not be better to have a controlled action to stop the train. The wheels will have negligible "flat spots" or imbalances as the material used has good abrasion, indentation and other properties to reduce the loss of material when grinding between the wheels and the track occur. Friction is the only way to stop the train, so by controlling it or intermittently interupting it will serve no purpose.

Answer 7

Rango nailed it. Best answer for sure.