how can you tell if a train has a wheel flat

[thachieman350]

Does It make a certain noise as it passes ?

Thanks Jesse

 

[yorksrob]

A certain bump - bump - bump - bump .............

 

[ralphchadkirk]

You can hear them quite clearly if you know what you're listening for.

 

[driver9000]

A rythmic tapping sound as the train passes by.

 

[Ferret]

A rythmic tapping sound as the train passes by.

Can even get rough riding if it's a bad flat and you're on board the train...

 

[Schnellzug]

It goes clank-clank-clank-clank-clank-clank.

 

[driver9000]

Can even get rough riding if it's a bad flat and you're on board the train...

I've only had a flat so bad it could be felt once and I took the set out of service.

 

[the sniper]

Does It make a certain noise as it passes ?

Thanks Jesse

If you stand on a platform and container train passes, you'll usually hear a 'dum, dum, dum, dum' from at least one of the bogies, that's a flat.

 

[NSEFAN]

This youtube video demonstrates what a wheelflat sounds like.

The fast thudding is the flat, so you get an idea of how fast the wheel is turning.

 

[Ferret]

I've only had a flat so bad it could be felt once and I took the set out of service.

I've had one myself. All the old hands say that if you can hear it then it's not too bad, but if you can feel it then it's time to stop!

 

[CosherB]

Just listen to almost any 323 set. Seems to be a design feature!

 

[Railguy220]

How do trains even get wheel flats?

 

[fgwrich]

Slippery rails, heavy braking are probbably the most common cause of Wheelflats - Just listen to most Freightliner Flats for those!

 

[ralphchadkirk]

How do trains even get wheel flats?

When the axle stops moving and the train keeps going the steel wheel rubs against the steel rail wearing the wheel into a D shape. Happened to a heritage train I was working (as trainee guard) once. Dvr applied the brakes going down a slippery hill and the wheels on the BV locked up putting flats on them.

 

[RobShipway]

I remember years ago being on a Class 86 pulled train from London Euston to Birmingham with both mk2 and a mk1 coach with a guards van coach at the end. I was with my parents at the time in one of the second class compartments of the guards coach and we heard the same sound as was on the Video, but out coach had two flats on it so sounded twice as bad which made the ride uncomfortable.

The train had to keep to the branch lines of the West Coast line, as the fast line the wheels would have got damaged even more so, doing more than the 50mph the train ws doing. We ended up in Birmingham 1.5 hours late.

 

[driver9000]

Slippery rails, heavy braking are probbably the most common cause of Wheelflats - Just listen to most Freightliner Flats for those!

Doesn't even need to be heavy braking, all you need a decent length slide even with a light brake application (such as step 1 of a Pacer).

 

[Peter Sarf]

HSTs - it always seems to be the buffet coach that gets a flat. I suppose even the WCML MK3 rakes as well. To me the tap-tap-tap of a wheel flat makes me think of buffet cars !.

I always assumed the weight difference of a buffet coach (or perhaps one end) means the braking effort is hardest to support (friction/grip) under the buffet coach so those wheels are the first to let go, slide and develop a flat. Not sure buffet coaches are lighter though ?.

 

[ert47]

You know, I actually thought that 319s were suppose to make the clacking sound when travelling at speed! xD

 

[Peter Mugridge]

I've had one myself. All the old hands say that if you can hear it then it's not too bad, but if you can feel it then it's time to stop!

I've reported a few that were bad enough to be felt, one of which was particularly worrying as the thumping and the vibration kept suddenly stopping to be replaced by a squealing noise, ie the wheelset in question was actually locking up! This was at 100mph on the WCML in a Mk3; the guard refused to even come to listen to it!

Should I have kicked up a formal stink about that after arrival at Euston?

( Note - this was about 10 years ago now ).

 

[chris89]

I've reported a few that were bad enough to be felt, one of which was particularly worrying as the thumping and the vibration kept suddenly stopping to be replaced by a squealing noise, ie the wheelset in question was actually locking up! This was at 100mph on the WCML in a Mk3; the guard refused to even come to listen to it!

Should I have kicked up a formal stink about that after arrival at Euston?

( Note - this was about 10 years ago now ).

Very intresting. I come across that must have been early last year on a VT 221, just after leaving Haymarket on the way to Carlise, a lot of vibrations especially, as it seemed to come and go when reached a certain speed then dispear. But just put it down to sitting over/ near the bogie (Even though have in the past and never come across that before)

Chris

 

[TDK]

I've only had a flat so bad it could be felt once and I took the set out of service.

I have had a couple I have had to take out of service, a class 455 once where the pass com was pulled and I had a complete 8 car lock up, this cost a fortune and one on a class 150 I had the unit inspected by a fitter and it came out of service, there is a governing factor on the physical length of the flat that determines wheter the set comes out of service, I cannot remember the length but I think it is about 4" or 100mm
--- old post above --- --- new post below ---

I've reported a few that were bad enough to be felt, one of which was particularly worrying as the thumping and the vibration kept suddenly stopping to be replaced by a squealing noise, ie the wheelset in question was actually locking up! This was at 100mph on the WCML in a Mk3; the guard refused to even come to listen to it!

Should I have kicked up a formal stink about that after arrival at Euston?

( Note - this was about 10 years ago now ).

No not really, you did your bit by telling the guard, when a flat stops thumping is is usually on a curve and this indicates the flat is on one side of the wheel, this is very common in fact, you get the thump on a LH curve and nowt on a RH one, as for the squeeling this is probably flange squeal and not a wheel locked up,

 

[Peter Mugridge]

No not really, you did your bit by telling the guard, when a flat stops thumping is is usually on a curve and this indicates the flat is on one side of the wheel, this is very common in fact, you get the thump on a LH curve and nowt on a RH one, as for the squeeling this is probably flange squeal and not a wheel locked up,

In the case in question, the curvature made no difference. It seemed to be totally random; happening on both left and right hand curves and equally not happening on the left and right hand bits. The thumping got progressively worse as the journey continued. From memory I was on the train all the way from Carlisle to Euston. The vanishing thumping and replacement by squealing started about an hour into the journey; prior to that it had just been non stop thumping.

 

[dubscottie]

Another video of a flat..

http://www.youtube.com/watch?v=uT2DXO_xcU8&feature=related

And what can happen when a flat becomes a second flange..

http://www.railwaysarchive.co.uk/docsummary.php?docID=1155

 

[Flamingo]

I'm unable to get the picture to transfer (maybe some of the more technically minded members can), but if you go to the bottom of page 18 on the link here (into the Lavingdon crash), there is a really good picture of a worst-case flat. http://www.raib.gov.uk/cms_resources.cfm?file=/110407_R082011_Lavington.pdf

The train in question could only be moved at 5-10 mph.

 

[TDK]

In the case in question, the curvature made no difference. It seemed to be totally random; happening on both left and right hand curves and equally not happening on the left and right hand bits. The thumping got progressively worse as the journey continued. From memory I was on the train all the way from Carlisle to Euston. The vanishing thumping and replacement by squealing started about an hour into the journey; prior to that it had just been non stop thumping.

If the train had a dragging brake or a locked wheel it would have been stopped at some point, even a small flat makes a reasonably loud knock and also if you pass over some debris this will cause a knock also, you did right to tell the guard and that is all you can do unless you have experience or know what you are listening too

 

[AlexS]

Although as a wonderful cost saving measure these days most guards have nowhere near as much technical training as they once did and vary from really good to total crap in terms of knowledge/interest in how their train is running mechnically.

I once dropped a clanger and started a train out with a handbrake hard on. Unfortunately some kids in the next coach were ****ing about with the toilet and what I thought was the sound of water splashing out of the bog waste pipe was actually the wheelsets being dragged along the rail without turning. Most embarrassing, especially as wheelsets aren't cheap. Luckily the resulting flats wore out fairly quickly. I always have a quick walk through after taking over a train when it first starts rolling just to check everything sounds OK on the move.