Is there a differential gear box in railways?

Question

Is there a differential gear box in railways?

Answer 1

Well, not in the diesel-electric locomotives (and not in the 100 % electric locomotives too).  In the diesel-hydraulic ones there is a "kind of" gear box, the same in the diesel mechanical locomotives and diesel railcars.  But it is not like one of a car.

Answer 2

The purpose of a differential gear in an automobile is to allow the left and right wheels to turn at different speeds. This is needed when the car goes around a corner, since the wheel on the outside of the curve must travel farther than the wheel on the inside. If the wheels were attached to a solid axle (no differential) one of the wheels would have to scrape along the ground when taking a curve.

Railroad cars all have solid axles -- no differentials. That's why when a train goes around a sharp curve, the wheels squeal; one of the wheels on each axle has to scrape along the rail. Since trolley and subway systems have lots of sharp curves, and since lots of people are present to hear the noise from urban trains, this effect is especially noticeable on such transit rail lines.

Sometimes, railroads put rail oiling devices on the outside rail in a curve, to allow the wheels to slip more easily. This keeps the rails from wearing down so fast, both from the slipping wheels and from the force of the wheel flanges against the inner edge of the outer rail.

Answer 3

Locomotives do not use a gearbox. They are powered by electric motors, power is altered using voltage fluctuations.

Answer 4

I am a retired Union Pacific locomotive engineer.  Diesel Electric locomotives have electric motors mounted inside the truck (the part of the locomotive that contains the wheels and axles).  These motors transfer their power to the axle via a ring and pinion gear.  Similar to the differential on a car or truck, except that they mesh together in the same plane.  Where most cars or trucks mesh together at a 90 degree angle.  These have different gear ratios based on the needed speed of the locomotive.  Freight locomotives have lower ratios for heavy pulling and lower speed, while passenger locomotives have higher ratios for the higher speeds.  The limiting factor is the RPM of the electric motor.  To high RPM will start to unwind the windings in the motors.   Most freight locomotives have max speeds around 60 to 70 mph.

Most modern Locomotives do not have a geared transmission though.  They make what is called transition by switching electrically to different variations of parallel and series.

Answer 5

There is on some trains, those without axle mounted electric motors will have a type of differential - but it is different from cars, and is more designed to distribute the drive to the axles on a bogie rather then evening the speed of the the halfshafts

Answer 6

Nada-the power these days is "diesel-electric" first the diesel engine powers up-second the power from the diesel engine is used to "fire up"electric motors that are mounted on each set of wheels.They in turn power the steel wheels to turn,and its torque involved here,so they always start off slowly,just enough to grab the rails,in the winter and on inclines the engines have built in sandpipes that blow sand in front of the wheels ,so as to create friction producing traction-all this done by the engineer,who has a throttle that he moves one way to speed/the other slow[if he passes out a "deadman switch dumps air into the breaks and stops it suddenly]-I was a conductor for Conrail between Cleveland&Buffalo N.Y.[not a bad job if N.S.had'nt taken it over]Ciao!

Answer 7

TPHOGER has described the mechanical situation inside the locomotive. Outside the vehicle, remember that the wheels are tapered and they ride on rounded surfaced rail. As they go around a curve the truck with its wheels is shoved toward the outside of the curve and the wheels ride on the extremes of their taper, so that the same number of axle turns will pass over a longer distance on the outside rail, and a shorter distance on the inside rail ( on the narrower part of the wheel )

Mr Hoger has probably known this since he was  eight and so didn't realize it might be part of the Question.

Answer 8

no