350/1 "rocking out"

[bILLOO]

Yesterday I was returning home on one of the LM B'Ham/Crewe services from Euston. It was a little more "shaky" then usual, however when we were approaching Milton Keynes, the trains rocked quite violenty and we all assumed for a few seconds that the train was going to tip-up and there was quite alot of panic through-out the carriage.

Obviously this didn't happen, but it was quite scary. Is it "normal" for a train to rock like this? It wasn't even windy.

 

[142094]

Some trains do suffer quite badly from lateral movement, but this is mainly due to the track in some areas. Some lateral movement is normal, but if the driver was concerned he would report it.

 

[Schnellzug]

Desiros do tend to do that rather. I don't think any modern brand of rolling stock has really come up to the standards of the last types of BR stock in that regard, whatever else might be said for them.

 

[Nym]

The setup of the suspension on a 350 unit has very little damping to appose the motion of the suspension, if you excite it close to one of it's resonant frequencies (that should always be avoided) it will get quite violent, although I do beleive that the Desiro series have variable dampers in place to stop this from happening (I'm open to being corrected here) so said dampers will stop any resonance faster (by apposing all motion) but will make it a shakeyer ride.

The system again, I beleive, is electronically controlled, so if there was a failiure in this system it would well, not work. You wouldn't get anywhere near tipping though, I suspect the volent motion was the unit's suspension hitting the safety stops.

 

[Hydro]

How did it tip? Did it feel like a boat rocking on a wave? Could be a track defect exacerbated by the suspension.

 

[bILLOO]

How did it tip? Did it feel like a boat rocking on a wave? Could be a track defect exacerbated by the suspension.

Yes, that's exactly how it felt; like a boat on the approach to MKC. We had one sudden tip to the left as the line splits prior to the station and that's when people started to worry/panic. There was a longer than usual pause at MKC, but continued towards Northampton where the rocking stopped.

 

[Ticket Man]

You want lateral sway on a train try sitting on the DLR through Woolwich tunnel. In the first week of the extension being open, I saw an old lady get de-seated by the sway caused by the track.

Theres also a very shoddy set of points in between Slade Green depot and the station that makes my heart sink every time you hit them at speed, awesome to watch from the platform though!

 

[Nym]

Sounds a lot like a damping problem then

 

[oversteer]

I saw someone get bounced out of the seat on a Met line A60 stock once.

 

[Michael.Y]

I get bashed into seats, walls and my trolley frequently between Leominster and Church Stretton at 100mph on the 175s.

 

[Yew]

HST's suffer a bit in heavy wind, When I was on the MML the rough bit was particularly rough, like pacer ish. Well, maybe a different flavour of bouncing, more 'sharp'