Smooth departures

[Huntergreed]

I have noticed that when riding on VTWC trains, the smoothness of departure from each station always varies. Does anyone know why this is? I would simply assume the driver of the 390 would put the traction brake control in power mode 1 and that it would always feel the same?

 

[fowler9]

I have noticed that when riding on VTWC trains, the smoothness of departure from each station always varies. Does anyone know why this is? I would simply assume the driver of the 390 would put the traction brake control in power mode 1 and that it would always feel the same?

I would have thought it would depend on the speed limit (And changes of) plus the track conditions leaving a station.

 

[BestWestern]

Poor rail adhesion will cause the train to deliver a jolty, bumpy start. This problem is far more prevalent when moving off from a standing start. There is little that a Driver can do to cause a poor ride, other than excessive speed or braking, neither of which would apply when starting from a station of course.

 

[Phil.]

You want a jerky ride? Try a London - Norwich - London loco operated push-pull set. I've never known such a jerky ride all the times at all times of the year that I used to use them. It does seem to be worse with the loco pushing.

 

[scott118]

You want a jerky ride? Try a London - Norwich - London loco operated push-pull set. I've never known such a jerky ride all the times at all times of the year that I used to use them. It does seem to be worse with the loco pushing.

That might be that DK1 fella, spilling everyone's coffee..he is such a scamp.

 

[Bald Rick]

You want a jerky ride? Try a London - Norwich - London loco operated push-pull set. I've never known such a jerky ride all the times at all times of the year that I used to use them. It does seem to be worse with the loco pushing.

Always been the way with the loco pushing, as us former WCML commuters can testify heading southbound. The driver doesn't have the individual traction motor ammeters in the DVT, which usually provide the first indication of wheelslip, so he (or she) can adjust power accordingly.

 

[BestWestern]

An HST is always good for a lively ride when the road is greasy; it's like riding an accordian!

 

[Bromley boy]

For the ultimate in smooth departures, my "personal best" is definitely a Eurostar (373). The start is so smooth that it's imperceptible and I don't realise the train is moving until I look out the window.

I assume this is to do with the length of the train being pushed/pulled by the power cars at either end.

 

[AM9]

You want a jerky ride? Try a London - Norwich - London loco operated push-pull set. I've never known such a jerky ride all the times at all times of the year that I used to use them. It does seem to be worse with the loco pushing.

Surely that is because the push from the back progressively compresses the couplings between each coach. If you are at the front of 9 or 10 coaches, when the compression 'wave' reaches you the loco has increased speed a little which means that the bump is larger. Your coach then bouces forward stretching the coupling springs and then stops when they reach their limit. If the driver accelerates hard enough and the couplings have plenty of undamped compliance, it can set a peristaltic ripple up that may go through several cycles. This often happens when track adhesion is good.
I remember that the 4-REP + 2x4TC trains on the SWML could do this when pulling away on down trains when there was a 3200hp 4-car unit pushing 8 trailer cars.

 

[Ash Bridge]

Always been the way with the loco pushing, as us former WCML commuters can testify heading southbound. The driver doesn't have the individual traction motor ammeters in the DVT, which usually provide the first indication of wheelslip, so he (or she) can adjust power accordingly.

Must agree with you there, and if memory serves correct, the class 90s always seemed worst than the 86/87s in this respect.

 

[AM9]

For the ultimate in smooth departures, my "personal best" is definitely a Eurostar (373). The start is so smooth that it's imperceptible and I don't realise the train is moving until I look out the window.

I assume this is to do with the length of the train being pushed/pulled by the power cars at either end.

All other things being equal, the trains with the fewest trailers (i.e. those comprising all power cars) will be the smoothest pulling away.

 

[fowler9]

All other things being equal, the trains with the fewest trailers (i.e. those comprising all power cars) will be the smoothest pulling away.

I dream of a train made up of 153's.

 

[BestWestern]

I dream of a train made up of 153's.

Too gutless to produce any sort of power-related lumps and bumps!

 

[Bromley boy]

All other things being equal, the trains with the fewest trailers (i.e. those comprising all power cars) will be the smoothest pulling away.

Makes sense.

Anyone else noticed the class 373 smoothness? I'd love to know what causes it...

 

[scott118]

Makes sense.

Anyone else noticed the class 373 smoothness? I'd love to know what causes it...

articulated bogies?

 

[Peter Mugridge]

articulated bogies?

That's exactly it.

 

[craigybagel]

Try ATW's 158834, fitted with a 4 speed transmission. It's a lot quicker off the mark,but it keeps around something terrible, especially when coupled to another unit....

 

[Phil.]

For the ultimate in smooth departures, my "personal best" is definitely a Eurostar (373). The start is so smooth that it's imperceptible and I don't realise the train is moving until I look out the window.

I assume this is to do with the length of the train being pushed/pulled by the power cars at either end.

Just spotted your enquiry. It's a combination of power at each end and the Scharfenberg couplings being very tight with very little fore and aft movement.

 

[coppercapped]

Just spotted your enquiry. It's a combination of power at each end and the Scharfenberg couplings being very tight with very little fore and aft movement.

Pedant mode ON!

The only Scharfenberg couplers in the 373 are at the outer end of the power cars. The coupling/articulation between the coaches can best be described as a steel ring to which the ends of the coaches are pinned. The pin allows rotation along the longitudinal and lateral horizontal axes and the vertical axis but no relative up-and-down movement. There are 'ears' on each side of the ring which sit on top of the bogie's secondary suspension air springs.

As the whole train is linked - a bit like a bicycle chain on its side - all the coaches move up and down together which means there is no need for dampers across the primary suspension. This removes a vibration path and makes the ride smoother. The conventional bogies under the power cars and the first coach on the other hand do have the primary dampers.

Pendant mode OFF!

Together with careful control of the 3-phase motors to avoid any slip on starting, the result is a silky smooth ride.

 

[Smitham]

I remember when new the HSTs were so gentle pulling away you wouldn't know unless you were looking out the window.

 

[theageofthetra]

Any Networker combination with a 466 in it driven from that end in light rain or over a conductor rail gap.