How do trains run without a differential?

Question

As I know, there is no "differential" in trains. How do they mange curves and turns? There must be something with the wheels.

Answer 1

You have the radius of the curve which is slight and gradual which will cause a minimal amount of slippage,and if the rail is wet or greased you can have what they call flat spots in the rail and wheel.Reason is with no differential both wheels spin at same rate wearing down rail and wheel.   In both cases they have to be ground to be repaired or replaced.The reasoning for no differential is to provide the most torque with as little horsepower loss as possible.

Answer 2

The curves and turns are so slight that the straight (fixed) wheels can manuver with no problem. If they made the turns sharper then they could derail. Plus the wheel base (length between axles) is short enough to make the turns with out binding. also, if you notice how the wheels sit on the track, its almost the same as a roller coaster. The difference is a roller coaster has and extra wheel to hold it to the rail for the loops and stuff. Trains and train cars can be lifted right off the track.

Answer 3

uhh its the wheels cause  if you look at them they shape  keeps them on the tracks and when it turns the tracks push against the whell and force the train to move with the tracks thats why there is no sharp corners on train tracks cause it would probly just hop ova it  ...

Answer 4

The treads are tapered.  The circumfrence is greater near the flange than at the outsid rim.  

Theoretically, the wheelset will allign such that it is runing on a greater curcumfrence than the inside wheel.

HOwever, as they wear, this can't happen, and one or the other will skip.

The squeal is usually the flange grinding against the rail when conical tread can't turn the wheelset.

Answer 5

Its just steel wheels on steel rails. No need for differential.

Answer 6

While the curves are gentle, that is of little reason for for the question at hand. No, trains do not have differentials. They use electric motors that are directly coupled to the wheels. These are called traction motors. It is a special compound series motor designed for high starting torque, and moderate to high running speed. Wheel slippage, and gentleness of curves has nothing to do with it. IF one were to lift a locomotive completely off of the tracks, and run the driving engine to full power, the electric motors would continue to accelerate until they came apart. The "engine" is usually a diesel engine driving an alternator that makes electricity. The engineer controls his speed by controlling how much electricity is generated in part by the speed of the diesel, and in part by how much electricity the alternator (generator) produces. This in turn determines how fast the train moves, once it is up to speed.

Answer 7

The cars don't need a differential, they aren't driving the train, and each wheel set is free to spin on it's own axle.  

The engines have a different setup, with each electric motor driving two wheels thru a gearbox.  The gear box has a clucth-like disk that disconnects the wheel that doesn't spin as fast as the other.

Trains normally travel on tracks that have very gentle curves, but they do pass thru yards and sidings where the curves can be very sharp.  That's when you'll hear all the squeals and shreaks as the cars are forced thru tight switches and bends.

Answer 8

Nope just steel against steel, Course they do grease the rails believe it or not, Keeps steel from wearing out so fast. they do have sanders for traction

Answer 9

Curves and turns, When track is laid or resurfaced,there is a elevation to the outside rail ,graduated as to angle,tighter the turn

more ele.

Answer 10

there are steel on steel man. they will "spin or skip" the inside wheel that does not have to travel as far as the outside wheel, just like a welded set of spider gears in a street rod.

Answer 11

good question.  I didn't know trains dont have differentials

Answer 12

The wheels are smooth. The slippage is in the track.

Answer 13

The axles of the cars are indeed locked together.  The curves are so gradual that wheel slippage is minimal.  That's the high pitched squealing you hear when the train rounds a curve.

Answer 14

By differentials I'm guessing you are talking about the drive train? The way a locomotive moves is by a diesel motor inside the engine operates a generator and a air com-presser. As you increase the rpm's of the diesel you create amperage which drives the electric motors which in turn moves the wheels by a very large bunch of gears."To put it simply." The air com-presser supplies air to the train line so that you can stop the train with the brakes on the cars.

Answer 15

The corners are not curvered enough to reguire a differential.  Also a certain amount of slippage is allowed between the track and the wheels.