GWSR - What is that screeching sound? Fingernails down a blackboard?

I'm always on the lookout for Youtube videos showing a driver's eye view of the Laverton extension. I have come across a couple, one of which is http://www.youtube.com/watch?v=l6j1iCDPs8I and what I would like to know is what causes that god-awful intermittent screeching noise, particularly on the stretch from Toddington to Stanway viaduct? Plenty of good examples from 36secs onwards. If it is metal grinding on metal surely it is bad for the track and for the rolling stock used?

I was also going to ask why there appears to be a 10mph speed limit from Toddington to Stanway viaduct but maybe that too is something to do with the screeching problem.

Reminds me too much of fingernails raking down a blackboard... Aargh!!!

Best wishes,
Nigel

P.S. Truly sorry to hear of the recent metal theft. Hats off to the volunteers for their determination to keep the trains running no matter what.

 

It seems to be some kind of vibration or rattling to me rather than track noise (although there's some of that too), perhaps the driver's teeth rattling? Great cab view by the way, especially as I haven't had a chance to make that journey yet! Thanks for the link.

 

Definitely flange squeal. Quite a common noise from the footplate although it is more usually found on sharper curves.

 

So does flange squeal cause damage/wear to the wheel and/or track?

For those interested the link for the other cab view video I spotted is http://www.youtube.com/watch?v=7U0D55ZjXCQ

The poster of that video also posted one presumably taken at the same time from Hailes to Toddington - http://www.youtube.com/watch?v=gglbeSQrqW8

 

It's so frustrating isn't it!
Originally I would have thought it to be braking noises, but obviously not with the timings of the 'squeaks.'

 

As some background here.

The section to the viaduct is speed limited to 10mph as it is deemed to be within station limits.

The section of track from the brand new E15 turnout north of Toddington to the viaduct is recycled track laid to the best running edge, it is laid on SHC sleepers which gauge at 1432mm (back in the days when a reduced gauge was thought to stop high speed hunting of bogies). At the viaduct the line is laid on hardwood timbers and gauged to 1435mm and brand new rail, no squealing there.

The rest of the extension from the viaduct is CWR laid on majority of SHC sleepers with brand new rail.

On other areas of the GWR, also laid on SHC sleepers, slow speed squeals can also be heard i.e. Gotherington loop curve.

 

A clip of mine at the NVR demonstrates this actually very common noise quite well too...
http://www.youtube.com/we1330#p/u/14/EcDzG23-k20

Very Best Wishes,
Bob.

 

Thanks for the information, but does it (flange squeal) actually cause damage/excessive wear to the wheels or track?