Fastest accelerating MU on the continent?

[Jamesrob637]

I don't really know but maybe somebody with more experience could tell me. Possibly a Flirt or one such derivative? Or the new Pendolino? Answers on a postcard please...

 

[Mag_seven]

The Swiss "Flirts" are pretty fast off the mark.

 

[axlecounter]

Who knows.

Surely on dry rail FLIRTs can get up to speed really fast. And actually the driver can’t use the real full power the train could. When they came from the factory they could accelerate considerably faster, then the software was modified to get (slightly) softer accellerations.

 

[biko]

A FLIRT certainly could be a contender. I read that the acceleration of NS FLIRTs needed to be limited as they otherwise would be too fast at some level crossings after leaving a station.

 

[TRAX]

A FLIRT certainly could be a contender. I read that the acceleration of NS FLIRTs needed to be limited as they otherwise would be too fast at some level crossings after leaving a station.

Most, if not all, EMUs have a restricted tractive effort, because at 100% power they would be too powerful for their own good: they would slip all the time while accelerating. Usually EMUs (like Stadlers or Bombardiers) have a boost function (called PMax in France for Puissance Max (Max Power)) to unlock 100% power for a short while to allow overtaking of another train or to catch up time.
100% power can also be used to haul another dead train in an emergency.

 

[DanielB]

There's a significant difference however between restrictions on tractive effort built in by the supplier and safety related restrictions. The latter is the case with the FLIRT trains operated by NS, these had their acceleration limited even further to bring it more in-line with other stock to avoid problems with level crossings.
And even that was nog enough: there has been a situation at Dordrecht Zuid station where a FLIRT had to stop at the end of the platform (within the track section triggering a nearby level crossing), as a FLIRT accelerating after stopping at the normal location would have already passed the level crossing before the barriers had fully closed.

When I remember correctly the FLIRTs operated by Keolis NL don't have the additional restriction as they need to be really fast: fast acceleration was one of the requirements to enable opening of Zwolle Stadshagen station, which has been a ghost station for more than a year when ProRail found out after completion of its construction that the station did not fit in the timetable.

 

[biko]

When I remember correctly the FLIRTs operated by Keolis NL don't have the additional restriction as they need to be really fast: fast acceleration was one of the requirements to enable opening of Zwolle Stadshagen station, which has been a ghost station for more than a year when ProRail found out after completion of its construction that the station did not fit in the timetable.

A bit off-topic: I don't know if they are restricted as the NS ones, but I do know they cannot have considered Zwolle Stadshagen when building the trains, as the trains were being built at the same time as the station was built. Maybe they don't need to be restricted because there are no level crossings which can be triggered too late on the two routes they run on? Or they changed the trigger locations?

On topic: I can find acceleration of FLIRTs is around 0.8 to 1.2 m/s^2. The FLIRTs that will be delivered for Transport for Wales will have an acceleration of 1.1 m/s^2 (https://www.stadlerrail.com/media/pdf/fwbbmu0519e.pdf). I don't know if that is high from an international point of view, but in the Netherlands, this is one of the best accelerations. I think there might be better performers elsewhere as Dutch trains use DC and AC should be able to give more power.

 

[JonasB]

The fastest accelerating MU is most likely some kind of commuter train. The X60 used around Stockholm are with 1.12 m/s2 slightly faster than the TfW Flirts.

 

[Jamesrob637]

The fastest accelerating MU is most likely some kind of commuter train. The X60 used around Stockholm are with 1.12 m/s2 slightly faster than the TfW Flirts.

I remember those to Solna and didn't think they were exceptionally quick. Maybe just not from Solna.

 

[BRX]

Is there a theoretical maximum acceleration for steel wheels on steel rails? I guess it depends on the weight on the axle too?

 

[duesselmartin]

I don't really know but maybe somebody with more experience could tell me. Possibly a Flirt or one such derivative? Or the new Pendolino? Answers on a postcard please...

certainly in Germany the Class 420 and the later 425 feel fast in acceration although its potential is often not used.
(slowest seem to be the 6.28 DMUs)
What is statistically the fastest seem impossible to guess.
Martin

 

[AverageTD]

The fastest accelerating MU is most likely some kind of commuter train. The X60 used around Stockholm are with 1.12 m/s2 slightly faster than the TfW Flirts.

Was going to suggest something Coradia related. I remember the 1440s on the S8 in Dusseldorf took off exceptionally fast

 

[DanielB]

certainly in Germany the Class 420 and the later 425 feel fast in acceration although its potential is often not used.

They are fast indeed. Found some data on the NS SLT which is based on the BR425 and these appear to have an acceleration of 1.69 m/s^2.

The fastest MU in The Netherlands is actually the oldest stock: SGM is able to accelerate at 2.3 m/s^2, even slightly faster than a four-car DDZ (with the mBk as built-in loco). Although those accelerations are often not reached over the full range under the Dutch 1,5 kV DC.

 

[Irascible]

Is there a theoretical maximum acceleration for steel wheels on steel rails? I guess it depends on the weight on the axle too?

Emergency braking performance will give some idea. Theoretical maximum will require the theoretical ideal rail-wheel condition, which is somewhat unlikely... I think the likely max coefficient of friction is usually taken to be about 0.5, but practically ( or operationally ) it's a little less than half that. It's also not a static figure across speed ranges & obviously wheel loads change in motion.

Nio high-speed maglev left in Europe now, is there?

 

[duesselmartin]

No High Speed Maglev left. The test centre in Germany is derilict now.