Class 222/1 performance

[londonmidland]

On Monday, I boarded 222104 from Leicester to St. Pancras. This is a 4 coach 222. Being a frequent user of the 222s, one thing I noticed was how quick off the mark it was out of stations, as it felt faster to accelerate compared to a 5 or 7 coach variant. It felt as though I was on an EMU. I saw it again, later at night, heading north out of Leicester and it flew out the station.

Am I right to say all 22x have slightly de-rated engines compared to their design spec?

If so, what made this feel faster than the rest of the 222s?

I can think of some possible answers:
- Driver handling
- All engines working
- Less carriages = less weight vs more engines on a longer and heavier 222, which doesn’t offset performance vs extra weight evenly?

 

[gimmea50anyday]

the traction system of the voyager/meridian/pioneer fleets is essentially that of an electric train, just with an on board electricity generator rather than from a juice rail or overhead knitting...

 

[hexagon789]

On Monday, I boarded 222104 from Leicester to St. Pancras. This is a 4 coach 222. Being a frequent user of the 222s, one thing I noticed was how quick off the mark it was out of stations, as it felt faster to accelerate compared to a 5 or 7 coach variant. It felt as though I was on an EMU. I saw it again, later at night, heading north out of Leicester and it flew out the station.

Am I right to say all 22x have slightly de-rated engines compared to their design spec?

If so, what made this feel faster than the rest of the 222s?

I can think of some possible answers:
- Driver handling
- All engines working
- Less carriages = less weight vs more engines on a longer and heavier 222, which doesn’t offset performance vs extra weight evenly?

Yes, all 22x engines are derated from the original 750hp to 700hp.

Weight won't really come into it - the power-to-weight ratio actually improves marginally as you go up the sets in length, the driving cars weigh slightly more than the intermediates plus you have the benefit of less wind resistance on subsequent cars with the longer sets so that each additional car is having to extend less effort to overcome wind resistance.

The one advantage will be a 4-car set will clear a speed restriction the quickest because the back-end will exit a PSR sooner than a 7-car set but that will be less important at higher speeds.

Perhaps you just got a driver who just went straight into full power getting away rather than working up the power gradually to full?

 

[londonmidland]

Perhaps you just got a driver who just went straight into full power getting away rather than working up the power gradually to full?

I’d say this was the case, as the initial speed up from 0-40mph was very fast, as opposed to gradually accelerating.

 

[hexagon789]

I’d say this was the case, as the initial speed up from 0-40mph was very fast, as opposed to gradually accelerating.

There's a good video on YouTube of a driver accelerating a set away after a signal check in full power from a stand. I think ~80mph was obtained by the next signal. I'm not sure if the video dates from pre- or post-derating though