Class 172 Bogie Noise

[150001]

Travelling on London midland 172342 yesterday in the centre carriage and soon as we start moving there is a regular rhythm banging noise. I knew it was from coming from the wheels as they turned and it got slightly quieter at higher speeds. I've heard it on 172331 and 172341 before but it was only very quiet. Anyone know what the problem is because it sounds like the wheels need replacing or something?

 

[causton]

That would be a wheelflat I guess, where the wheels are no longer round due to friction between the track and wheel rubbing part of the wheel away, usually after heavy braking.

 

[WestCountry]

Happens a lot at this time of year due to slippery leaf mulch all over the place - brake too hard and the wheels just slide along the rail without rotating, which scrapes a flat spot.

 

[fgwrich]

Travelling on London midland 172342 yesterday in the centre carriage and soon as we start moving there is a regular rhythm banging noise. I knew it was from coming from the wheels as they turned and it got slightly quieter at higher speeds. I've heard it on 172331 and 172341 before but it was only very quiet. Anyone know what the problem is because it sounds like the wheels need replacing or something?

If it's a semi regular knocking noise then I would put that down to the design of the bogies - I've been hearing the same thing on the 220s for several years now.

 

[150001]

Would make sense if the wheels were wearing down (wheelflat) and yes, it is like a semi regular knocking noise. Thanks for the replies.

 

[455driver]

The wheel wont have a flat across its whole width (because the wheel is wider than the rail and will 'travel' across the rail as the wheel corners) so it might be quieter when turning one way than turning the other.

 

[edwin_m]

I believe it's not actually a piece ground out of the wheel directly, but the heat from the sliding turns the steel around the contact area into a more brittle form which then crumbles away.