Remarkable hunting oscillation

[Tobberz]

Hello hello. On a curve between Rugby and Milton Keynes yesterday, we were subjected to pretty remarkable side-to-side rocking aboard an LNR 350. I travel by rail a lot, and have never encountered it before. It was a busy train, and people really had to hold on tight!

I am not an expert, but having looked it up I assume it was "hunting oscillation". Is this sort of thing typical/common? And at what stage ought one worry?

 

[Sad Sprinter]

Last time I experienced it was back in March on the Acela Express racing through New Jersey. That was pretty bad and caused some concerned looks from the passengers. But the absolute worse was a few years ago, much closer to home, between Ealing Broadway and Slough. It was reallly bad and genuinely felt like the train couldn’t possibly stay on the track for much longer. Although the hostess on board seemed it wasn’t the first time that day she’d have that concern raised…

 

[m0ffy]

I experienced this a few weeks ago on the same section of track. It threw my (sealed) drink into the lap of a passenger across the aisle.

 

[fgwrich]

Without turning this into an anti IET thread (we know what happened to the last one this weekend!), the worst oscillation I’ve encountered is on the lightweight skateboard bogies under particular cars on the 80X fleet. I wonder if the stiffness of the couplings doesn’t help, as well as the ride quality offered by the bogies themselves?

I’ve found it particularly noticeable along 125MPH stretches of the GWML and a little on the East Coast as well.

 

[Russel]

Can't say I've noticed it anywhere outside of the DLR myself.

 

[Jimini]

Without turning this into an anti IET thread (we know what happened to the last one this weekend!), the worst oscillation I’ve encountered is on the lightweight skateboard bogies under particular cars on the 80X fleet. I wonder if the stiffness of the couplings doesn’t help, as well as the ride quality offered by the bogies themselves?

It's been a couple of years now (it's since been sorted I guess), but the down main at Airport Junction used to be quite the bumpy ride!

 

[The exile]

I was too young to remember the details, but hunting oscillation on the restaurant car (or whatever passed for one) on the Waterloo - Exeter (that dates it!) got the family a free afternoon tea - in the sense that it became so violent that we were invited to move seats and start again!

 

[sh24]

It's been a couple of years now (it's since been sorted I guess), but the down main at Airport Junction used to be quite the bumpy ride!

It was rather sporty! Fixed last year I think.

 

[Sad Sprinter]

Without turning this into an anti IET thread (we know what happened to the last one this weekend!), the worst oscillation I’ve encountered is on the lightweight skateboard bogies under particular cars on the 80X fleet. I wonder if the stiffness of the couplings doesn’t help, as well as the ride quality offered by the bogies themselves?

I’ve found it particularly noticeable along 125MPH stretches of the GWML and a little on the East Coast as well.

You been it’s been 24 hours since the last IET hate thread? Better start a new one…

 

[southern442]

I've noticed it to be very bad on class 180s on certain stretches of the ECML.

 

[Jimini]

To turn it from the IETs to the 387s ( ), on GWR they're quite lively when running on the relief lines, certainly from Paddington to beyond Slough.

But yeah, as pointed out upthread, we'll be hard pressed to find a better one than the DLR!

 

[renegademaster]

Noticed very bad ride quality a few weeks ago on the single track line from Alton especially given the desiros typically have good ride quality.

 

[185143]

I've noticed it on IETs between Paddington and Reading for sure. But only certain units. This was a couple of years back during the cracking issues when I was on a Thames Rover have a red pen fest of all the hired units, IETs and Wetherspoons I needed.

I remember one particularly bad IET and thinking we were surely about to come off. Yet gone over the same section of track 2 hours later in the same conditions and it's been fine.

I've just done an Azuma back from Aberdeen to Edinburgh. Aside from the curvature of the line, that was very smooth.

 

[Mcr Warrior]

Always used to be quite bad in BR days on the ~2 km section of Altrincham line track between Dane Road and Stretford, and this was still the case, post June 1992, after conversion from heavy rail to operation by trams. @507 001 might well know if 'hunting' is still a problem on this, or other parts of the Metrolink network.

 

[185143]

Always used to be quite bad in BR days on the ~2 km section of Altrincham line track between Dane Road and Stretford, and this was still the case, post June 1992, after conversion from heavy rail to operation by trams. @507 001 might well know if 'hunting' is still a problem on this, or other parts of the Metrolink network.

I seem to remember parts of the Oldham metrolink line being bad for it too.

 

[800301]

To turn it from the IETs to the 387s ( ), on GWR they're quite lively when running on the relief lines, certainly from Paddington to beyond Slough.

But yeah, as pointed out upthread, we'll be hard pressed to find a better one than the DLR!

From up front there are certain 387’s on certain bits of track that do get the hunting oscillation quite bad, normally from around 90mph upwards, there have been times I’ve been standing on Ealing Broadway platform as once passes and you can really feel the force through the platform, don’t tend to notice it as much from an 800 unless you’re a passenger

 

[Ashley Hill]

143s were prone to hunting coming off the Bristol lie at Cogload Jct.

 

[dk1]

It used to be absolutely thrilling on Liverpool St-Norwich intercity DBSO/MK2s back in the day. it wasn’t uncommon for these services to be doing 115-120mph after Diss. Going into Flordon dip on many occasions with tables rattling as the coach shook will always stay with me.

 

[507 001]

Always used to be quite bad in BR days on the ~2 km section of Altrincham line track between Dane Road and Stretford, and this was still the case, post June 1992, after conversion from heavy rail to operation by trams. @507 001 might well know if 'hunting' is still a problem on this, or other parts of the Metrolink network.

It is indeed.

 

[D1511]

As others have said, the DLR takes some beating.....the section between Canning Town and West Silvertown is like a transverse rollercoaster.......which is slightly unnerving as it's largely elevated and it would be quite a fall to N Woolwich Rd!

 

[FrontSideBus]

Worst I have experienced was on a 395 at 140mph! I was seriously contemplating finding the guard!
Do they count as IET's?

 

[NSEWonderer]

Worst I have experienced was on a 395 at 140mph! I was seriously contemplating finding the guard!
Do they count as IET's?

Don't lumber 395s into that. They've been very sound majority of the time.

 

[nlogax]

As others have said, the DLR takes some beating.....the section between Canning Town and West Silvertown is like a transverse rollercoaster.......which is slightly unnerving as it's largely elevated and it would be quite a fall to N Woolwich Rd!

The inevitable by-product of stock built to navigate sharp curves but it's always an entertaining ride when heading to City Airport.

 

[didcot_watcher]

How does this hunting compare to the 1992 stock on the east end of the central line?

 

[Russel]

As others have said, the DLR takes some beating.....the section between Canning Town and West Silvertown is like a transverse rollercoaster.......which is slightly unnerving as it's largely elevated and it would be quite a fall to N Woolwich Rd!

It's a lot more noticeable when sitting rather than standing on the DLR I find.

 

[PlatformEdgeVT]

Always used to be quite bad in BR days on the ~2 km section of Altrincham line track between Dane Road and Stretford, and this was still the case, post June 1992, after conversion from heavy rail to operation by trams. @507 001 might well know if 'hunting' is still a problem on this, or other parts of the Metrolink network.

On the topic of the Metrolink, the section on the Altrincham line between Deansgate Lane Junction and Navigation Road has a lot of hunting oscillation.

 

[DelW]

I've noticed it on IETs between Paddington and Reading for sure. But only certain units. This was a couple of years back during the cracking issues when I was on a Thames Rover have a red pen fest of all the hired units, IETs and Wetherspoons I needed.

I remember one particularly bad IET and thinking we were surely about to come off. Yet gone over the same section of track 2 hours later in the same conditions and it's been fine.

It seems to me to be a particular combination of speed, track geometry, and coach suspension characteristics (or wear) that causes it. On a couple of occasions on IETs I've had a short period of severe side to side shaking on the Didcot to Swindon section, yet I've been over that stretch dozens of times in similar trains without any disturbance. IIRC it occurred at relatively low speed, so I think there's probably some sort of harmonic frequency involved.

 

[wimbledonpete]

Worst I have experienced was on a 395 at 140mph! I was seriously contemplating finding the guard!
Do they count as IET's?

In the London-bound tunnel just after Dagenham? Was quite scary for a bit - haven't felt it for a while now though.

 

[FrontSideBus]

In the London-bound tunnel just after Dagenham? Was quite scary for a bit - haven't felt it for a while now though.

Seemed to happen whenever the speed exceeded 100-110mph!

 

[superalbs]

I've had a pretty bad experience on the Berks & Hants line, needless to say it was on an 800. We were shaking so much that my drink and earphone case were both moving across the table.