Class 323 wheel sound (not motors)

[LUKAnorthwest]

Hi all,

I've a question i've been meaning to ask for a while now. I notice a sound coming from the the last bogie at the rear of the train. It comes and goes and from my observations seems to be on straight track at around 50+ MPH. it seems to be a clunking sound, what i imagine to be the bogie hitting the underside of the carriage. some units seem to do this more than others and it does seem to happen in particular areas.

i have seen this on the up glossop line while running through gorton and fairfield. i am not referring to the clunking that occurs when the train goes over points.

so my question is this. what is causing this to happen and what is actually happening?

 

[Bletchleyite]

Most probably wheelflats, caused by the wheel sliding if it locks up on braking. 323s always seemed to be very susceptible to that problem. If so it'll be a consistent sound, one "bang" per wheel rotation.

If you mean odd bangs when going over a bad bit of track, that's the suspension hitting the stops. Though I never noticed that as much on stock newer than Mk3 EMUs (<=322). Similarly some units have a bit of side-to-side play in suspension/bogie mounts, but again I don't recall 323s having a lot of that.

If it gets too bad, a visit to the wheel lathe is required to round them back off.

 

[LUKAnorthwest]

If you mean odd bangs when going over a bad bit of track, that's the suspension hitting the stops. Though I never noticed that as much on stock newer than Mk3 EMUs (<=322).

Thanks for that, this seems to be the most logical answer, it is just the rear bogie in the last carriage and only happens for around 2 - 3 seconds at certain locations. i did think it was bad track but wasn't sure what was happening with the unit.

 

[ANorthernGuard]

That unit is a noisy git. seems they forgot to put dampeners on (rubber) when it had a refurb a few years ago. It happens anywhere with a slight dip or similar.

 

[the sniper]

I know the sound you're talking about. To be honest I always thought it was the coupling bouncing on the bar on which it rests, as the sound seems to me to come from under the cab, though I could never fully understand how it could be weighted/jointed to do so! Suspension sounds plausible, except like the OP I don't recall ever hearing it from anywhere except at the rear of the train...

In LM land you often get it between University and Five Ways, if going at line speed, around the curve just south west of Church Road tunnel.

 

[Starmill]

They entire fleet seems to make a lot of 'secondary' noise, the sort of incessant sqeaking that they do and the slam every time someone uses those god damn internal doors. They aren't quite as unsettling as the 333 'knocking' noise in the bogies you get at 90mph!