Why do train wheels screech/sequel so much nowadays

[Western Sunset]

Listen to a train leave Euston and the wheels screech and squeal. Same at Kings Cross, Paddington, you name it.

Why?

I'm sure there weren't such high-pitched noises from wheelsets twenty years go. Just wondering why.

 

[edwin_m]

I think it's to do with modern bogies, which are stiffer in rotation to reduce the lateral oscillation or "hunting" that was a big problem in the 70s. As they are stiffer they are less able to align themselves on tight curves so the flanges are more likely to contact.

 

[deltic08]

Listen to a train leave Euston and the wheels screech and squeal. Same at Kings Cross, Paddington, you name it.

Why?

I'm sure there weren't such high-pitched noises from wheelsets twenty years go. Just wondering why.

Longer distance between wheelsets in a modern bogie. Pacers with effectively one long single bogie, were around 35 years ago and squealed but not at London termini naturally

 

[coppercapped]

In the case of Paddington the trains accelerate more quickly than in days of yore...

(Squealing seems to me to be to be more prevalent on the lower number platforms which have tighter radius curves as well as above 12 where the line limit is only 25mph).