Why Do Train Wheels Screech on Curves?

In summary, the screeching sound of train wheels on curves is caused by the conical shape of the wheels, which shifts the contact on the outer and inner wheels to different diameters. The flanges on the wheels are only a last resort to keep the train on the rails. The scraping noise is caused by the occasional contact of these flanges due to various factors.
  • #1
Philip Chen
1
0
Does anybody know why you hear the train wheel SCREECH when the train makes a curve?
 
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  • #2
My guess would be that the axle is solid so at least one of the wheels has to be slipping since the outer and inner tracks are different lengths.
 
  • #3
russ_watters said:
My guess would be that the axle is solid so at least one of the wheels has to be slipping since the outer and inner tracks are different lengths.

This is actually taken into account. The wheels of a train are conical. When the truck (set of wheels) goes around a curved section of track, it moves outwards. This shifts the contact on the outer wheel to a larger diameter part of the wheel, while the contact on the inner wheel is moved to a smaller diameter.

http://www.railway-technical.com/whlbog.shtml" .

The fact that the wheels are conical is also what keeps the wheels on the rails, not, as seems intuitive, the flanges. The flanges are only a last resort.

And to answer the OP's question: It is the occasional contact of these flanges - due to incorrect geometry, poor maintenance or wrong speed - that causes the scraping noise.
 
Last edited by a moderator:

1. Why do train wheels screech on curves?

Train wheels screech on curves due to a phenomenon called "wheel/rail squeal." This occurs when the train's wheels and the track's rails come into contact at an angle, causing vibrations and a high-pitched noise.

2. Is it dangerous for train wheels to screech on curves?

While it may be unpleasant for passengers, train wheels screeching on curves is not necessarily dangerous. It is a natural occurrence and does not indicate any immediate safety concerns.

3. Can screeching train wheels cause damage to the train or tracks?

In most cases, screeching train wheels do not cause any significant damage to the train or tracks. However, if the screeching is excessive or occurs frequently, it can lead to increased wear and tear on the train's components and the tracks.

4. Does the speed of the train affect the screeching of the wheels on curves?

Yes, the speed of the train does affect the screeching of the wheels on curves. The faster the train is moving, the more likely it is to produce a louder and more noticeable screech. This is because the wheels are rotating faster and creating more friction with the rails.

5. How do train engineers reduce the screeching of wheels on curves?

Train engineers can reduce the screeching of wheels on curves by implementing various measures, such as using lubricants on the rails and wheels, adjusting the train's speed, and maintaining proper wheel and track maintenance. Additionally, newer trains may have design features that reduce the occurrence of wheel/rail squeal.

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