The interesting engineering behind the shape of train wheels

On turns, it is true that the conical shape helps. However, there is still significant additional rail wear on turns. So I assume the conical phenomenon does not totally cancel all the non-perpendicular rail forces. I also read somewhere that some early designs had the wheels on the outside of the track. This apparently actually worked, but made switch configuration more complex.
 
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Some transit systems have sharp curved track that cause the squealing noises when trains run on them. Before the old South Ferry station closed, some people covered their ears when trains ran on inner loop.
 
The Boylston Street curve onto Park Street is pretty tight and one of the tightest of any transit system and the sharpest curve in North America.

Why The MBTA's Wheels Squeal — And How It's Trying To Dampen The Noise | WBUR News

https://youtu.be/YfPWY_1U53w

The tunnel leading to the station has a 5 mph curve. When Breda made the first batch of trolleys, they didn't follow directions and used standard bogeys. When the trams were tested, they got stuck in the tunnel and caused millions in damages. The "T" ended up retrofitting the batch at Breda's expense plus Breda paid to have the tunnel repaired.
 
Interesting article with the different ways to try to lubricate the track and wheels. And double whammy with trains going both ways in the video!
 
Forester1 said:
Interesting article with the different ways to try to lubricate the track and wheels. And double whammy with trains going both ways in the video!
Click to expand...

That inside curve is really tight! Imagine a light rail vehicle derailing in that tunnel.
 
I know that motor vehicles have differentials on driving axles so that the wheels can turn at different speeds when motor vehicles make turns. Why not trains?
 
The French do that with their some of their subways, they even put pneumatics on them, such as the Paris metro type MP73. It does reduce the noise greatly. The technology was indeed developed from motor vehicles by Regie Renault.
They also made tests without pneumatics on the MF88 with a very different design, there is literally no noise in the curves, but that unorthodox axle design proved to be too maintenance intensive to be used on a great scale.
 
Thus, the need for rail-grinders and the spectacular light show they provide. The shape/geometry of the rail must be maintained.

 
We have a problem with our Metro trains in Adelaide with the wheels "hunting" badly after only 5 years of use. I am in a wheelchair and have to sit in the front of the train directly over the wheels. The shaking is so bad the trains have to run slower due to it, making timetables hard to keep to. Some trains were bad from the start. It appears they are finally starting to regrind the wheels now. I only have a 10 minute ride, used to be 6 minutes. I really feel sorry for people doin the 1 hour run to Adelaide. The track was laid down at the same time the trains were brought in. One long stretch where they used to run at 90km/hr now the run less that 70 km/hr.
cheers,
Mike
 
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