What causes the screeching sounds that trains make as they make turns?

Question

I assume it has something to do with the different distances the inside and outside wheels are traveling, but am not sure.

Answer 1

The screeching is metal to metal friction contact.    Could be brakes,  but  most often the train is not braking.    The noise you are hearing is most likely the metal wheels rubbing against the inside of the rail as they try to continue to go straight ahead.

A regular part of train maintenance is the replacing of the steel wheels when they have been worn down past an acceptable level.

Answer 2

Pressure on the axlebearings and sharp curves

Answer 3

train wheels are metal. the tracks are metal. anytime you have metal to metal you have screeching. but when they turn it increases due to one side turning faster

Answer 4

The side of the wheel hitting the track can cause that noise it can also be the brakes applying to slow train down at curve.

Answer 5

Flange bind in curvature.  Most tight curves have "greasers" on both ends, which automatically shoot grease onto the wheels to help the flange bind.

In addition, curvature usually consists of steel with a higher amount of carbon making them extremely tough, though a bit more brittle.

Answer 6

Yes, It is related to the differentiation in speed between the inner wheel and out  wheel in a turn. The surface speed of the outer wheel is higher than that of the inner wheel. Reason is the outside track has a larger radius and causes it's respective wheel to spin faster. Since the axles on trains are"live" both wheels connected, the inner wheel spins at the same RPM and actually skids or Screeches on the track.

Also the flanges on the inner side of each wheel will touch the track in a turn, they keep the train from jumping off of the rails, this radial pressure exerts extreme force on both the wheels and rails. The difference in wheel speed and pressure exerted by wheel flanges cause the screech. It is also very neat to watch at night, there are often sparks seen comming from the wheels.

Answer 7

In New York City Subways, they make lots of screeching sound mostly at curved track. It's wheels of NYC Subways.

However, New Jersey Transit's lightrails, Hudson-Bergen Lightrail and RiverLine is only quiet train.

Answer 8

Yup, it's primarily the wheel flanges. Railroad wheels by design are self-centering on the rails, and the flanges don't contact anything on straight track. But on curves, the flanges rub against the outside rail.

Answer 9

Also trains slow down on corners so the train doesn't tip over or the flanges don't break off, just to let you know =).

Answer 10

The wheels have sides (flanges) so the trains don't fall off the track. Going around a turn causes pressure to be applied to the sides of the wheels (a heavy object wants to keep moving in a straight line) and they rub hard against the sides of the track to turn the train.

http://www.bbc.co.uk/science/hottopics/t...

"A pair of wheels are fixed to an axle. The 'tyre' - the only part of the wheel sitting on the rail - is conically shaped. This enables the wheels to fit snugly into the tracks. The weight of the vehicle, together with the shape of the tyres, allows the train to follow the track without guidance or steering.

The problem begins when a locomotive engine weighing hundreds of tonnes enters a bend at high speed. The wheels - carrying a load of over 12 tonnes each on an area the size of a five-pence coin - are forced to change direction by the rail. \

A raised collar on the inside of the wheel (called the 'flange') provides an extra safety measure to prevent de-railing. Under normal circumstances, the flange shouldn't touch the rails. Unfortunately, this is not always the case.

Centrifugal force pushes the wheel against the rail on the outside of the curve, and the wheel flange exerts an enormous amount of pressure against the rail.

Under normal circumstances, the hardened steel rails used on British networks will withstand such extreme pressures. However, carrying 60 trains a day, seven days a week takes its toll. Without constant surveillance by maintenance crews, the rails can become a ticking time bomb."

Answer 11

Brakes slowing down the train so it doesn't fly off the tracks.