Why?

[D Cody]

Why is it that some cars sound like they have square wheels on them?
I walk along side of a major North-South route of Burlington Northern and you can here cars coming from along way off by the clankings of their wheels. I thought at first it was joints in the track but it it only happens
on some cars.
Just really curious
Dean

[dave1905]

If the handbrakes aren't fully released, the brakes set up fully on a car while the train is still moving or the brakes don't release fully or release slowly the brakes may be on and the wheels stopped rotating while the train is moving. That ends up with the wheels sliding along the rail and grinds a flat spot in the wheel. The flat spot has to be over 2 inches long to be defective. If its less than that its just noisy.

[diburning]

It can also happen over time from hitting switch frogs and bad joints at speed although that just causes little chips and dents that don't cause much noise.