Differences Between Various Sprinters Acceleration

[gazthomas]

True, as un-"super"b as they were

I love the irony

 

[hexagon789]

I love the irony

Seemed to have a lot of issues when new, particularly compared to say 150s or 156s. Plus the 153s converted from same are among the most sluggish DMUs acceleration wise

 

[Railperf]

Yes, the 153 i sampled between Norwich and Great Yarmouth -packed like Sardines on a sunny Saturday last May - was dreadfully slow, but it did have fair amount of extra weight to carry that day - having been drafted in to substitute for a missing 755/4.

 

[Railperf]

Interested to note that a 2+6 HST formation has the closest power to weight ratio to a Class 222. The HST is apps 10,5hp/t at the rail compared to between 10.56 and 10.8 for a 222. The 222's seem to deliver appx 525 to 540 rail hp per engine.
A 2+5 HST is much higher at 11.6 hp/t and the 2+4's are almost 13.1hp/t.
Still, even a 2+5 HST struggles to keep up with a Voyager in the initial 0-30mph sprint, mainly because of the way that power is more gently applied - also linked to how quickly the HST brakes will release.
The 22x's - being true multiple units (HST's while called multiple units are essentially 2 locos either side of a rake of conventional coaches) seem to release the brakes quicker and the traction system - being far more modern - seems able to deliver power earlier to deliver that faster start. The HST's 1970's traction system seems to require a more gentle application of power - the general feeling that Notch 5 starts are likely to cause them to fail more frequently due to overloading the traction electronics.

It is fascinating to see that improved technology allows the Class 755's to have a power pack that is as potent as an HST power car , but in a more compact space.

 

[hexagon789]

Yes, the 153 i sampled between Norwich and Great Yarmouth -packed like Sardines on a sunny Saturday last May - was dreadfully slow, but it did have fair amount of extra weight to carry that day - having been drafted in to substitute for a missing 755/4.

Data I have suggested that a 153 was over 30 seconds slower to 60mph than the next poorest member of the Sprinter family

 

[hexagon789]

Interested to note that a 2+6 HST formation has the closest power to weight ratio to a Class 222. The HST is apps 10,5hp/t at the rail compared to between 10.56 and 10.8 for a 222. The 222's seem to deliver appx 525 to 540 rail hp per engine.
A 2+5 HST is much higher at 11.6 hp/t and the 2+4's are almost 13.1hp/t.
Still, even a 2+5 HST struggles to keep up with a Voyager in the initial 0-30mph sprint, mainly because of the way that power is more gently applied - also linked to how quickly the HST brakes will release.
The 22x's - being true multiple units (HST's while called multiple units are essentially 2 locos either side of a rake of conventional coaches) seem to release the brakes quicker and the traction system - being far more modern - seems able to deliver power earlier to deliver that faster start. The HST's 1970's traction system seems to require a more gentle application of power - the general feeling that Notch 5 starts are likely to cause them to fail more frequently due to overloading the traction electronics.

It is fascinating to see that improved technology allows the Class 755's to have a power pack that is as potent as an HST power car , but in a more compact space.

Is it only up to 540hp? I thought the motors were rated at 275kW, even allowing for transmission losses I thought modern traction electronics were more efficient than the old 90% of 90% efficiency.

 

[Railperf]

Is it only up to 540hp? I thought the motors were rated at 275kW, even allowing for transmission losses I thought modern traction electronics were more efficient than the old 90% of 90% efficiency.

Since between spring and summer 2015 it is understood the engine management chip was remapped to lower power levels. Our recordings of Class 222 performance over the period show a marked reduction on power from appx 560 hp +/- 8 to 10 hp at the rail to a current level of apps 540hp +/- 8 to 10hp. Around Winter 2015/16 this was resulting in approx 20% of sets running with an engine out - down from appx 30%.
If you take the commonly quoted engine rating of 750hp, and relate that to the at rail figure of approx 575hp, that is essentially only 77% of the engine power actually getting to the rail.

 

[Railperf]

Data I have suggested that a 153 was over 30 seconds slower to 60mph than the next poorest member of the Sprinter family

Starting from Acle eastbound - reasonably level there - 0 to 60mph in 158 seconds!!

 

[hexagon789]

Since between spring and summer 2015 it is understood the engine management chip was remapped to lower power levels. Our recordings of Class 222 performance over the period show a marked reduction on power from appx 560 hp +/- 8 to 10 hp at the rail to a current level of apps 540hp +/- 8 to 10hp. Around Winter 2015/16 this was resulting in approx 20% of sets running with an engine out - down from appx 30%.
If you take the commonly quoted engine rating of 750hp, and relate that to the at rail figure of approx 575hp, that is essentially only 77% of the engine power actually getting to the rail.

I can understand down raring engines to reduce wear and fuel consumption but actively downrating performance of the traction electronics seems counter productive somehow

 

[hexagon789]

Starting from Acle eastbound - reasonably level there - 0 to 60mph in 158 seconds!!

Very similar to the figure I have of 159 seconds

 

[Railperf]

I can understand down raring engines to reduce wear and fuel consumption but actively downrating performance of the traction electronics seems counter productive somehow

I presume that trials were carried out - to determine if wear and tear could be reduced and reduce fuel consumption at a power setting that would still allow the timetable to be maintained - especially as 125mph running on MML had been introduced by then. And some of those 125mph sections are quite short - so a decent power to weight ratio needed to get to 125mph and maintain it for as long as possible.

 

[hwl]

I presume that trials were carried out - to determine if wear and tear could be reduced and reduce fuel consumption at a power setting that would still allow the timetable to be maintained - especially as 125mph running on MML had been introduced by then. And some of those 125mph sections are quite short - so a decent power to weight ratio needed to get to 125mph and maintain it for as long as possible.

Engine derated in software from 750 to 700hp
750hp -> 560kW
700hp -> 521kW
Around max of 45kW for hotel load and auxiliaries per car so 515/476kW for traction power and losses.
560hp -> 417kW allowing for auxiliaries so 417/476 = ~ 87.6% to traction at wheel from what is available (you'll struggle to get much over 90%).

 

[hexagon789]

I presume that trials were carried out - to determine if wear and tear could be reduced and reduce fuel consumption at a power setting that would still allow the timetable to be maintained - especially as 125mph running on MML had been introduced by then. And some of those 125mph sections are quite short - so a decent power to weight ratio needed to get to 125mph and maintain it for as long as possible.

You would assume they did perform trials, but again given the fact that the increases in permitted speeds on the MML were intended to reduce journey times, given that when the first 125mph timetable came into force it was said at the time they would reduce timings further, it seems more difficult to do that with a downrated fleet of trains.

That's my thoughts anyway.

 

[Railperf]

Engine derated in software from 750 to 700hp
750hp -> 560kW
700hp -> 521kW
Around max of 45kW for hotel load and auxiliaries per car so 515/476kW for traction power and losses.
560hp -> 417kW allowing for auxiliaries so 417/476 = ~ 87.6% to traction at wheel from what is available (you'll struggle to get much over 90%).

That seems to be in line with our findings. But as each set can differ in regards to engine health - the majority of recordings suggest average engine outputs per set in the region of 535 to 545hp - meaning one or more engines might not be pushing out their full bhp. The figures I have for late 2015 suggest very few sets averaging 550hp per engine. Nothing more than that.

 

[irish_rail]

Interested to note that a 2+6 HST formation has the closest power to weight ratio to a Class 222. The HST is apps 10,5hp/t at the rail compared to between 10.56 and 10.8 for a 222. The 222's seem to deliver appx 525 to 540 rail hp per engine.
A 2+5 HST is much higher at 11.6 hp/t and the 2+4's are almost 13.1hp/t.
Still, even a 2+5 HST struggles to keep up with a Voyager in the initial 0-30mph sprint, mainly because of the way that power is more gently applied - also linked to how quickly the HST brakes will release.
The 22x's - being true multiple units (HST's while called multiple units are essentially 2 locos either side of a rake of conventional coaches) seem to release the brakes quicker and the traction system - being far more modern - seems able to deliver power earlier to deliver that faster start. The HST's 1970's traction system seems to require a more gentle application of power - the general feeling that Notch 5 starts are likely to cause them to fail more frequently due to overloading the traction electronics.

It is fascinating to see that improved technology allows the Class 755's to have a power pack that is as potent as an HST power car , but in a more compact space.

A notch 5 departure is more or less impossible these days due to the MDEC computer (on the MTU power cars) doesn't allow instant full power. If driver puts it straight into notch 5 it will still take about 10 seconds or so before you are getting full power.

 

[londonmidland]

What's the performance difference between a 2+7 HST and a five car Voyager climbing the Lickey Incline both whilst climbing and also at the top, at Barnt Green? What speeds are they travelling at?

 

[Railperf]

What's the performance difference between a 2+7 HST and a five car Voyager climbing the Lickey Incline both whilst climbing and also at the top, at Barnt Green? What speeds are they travelling at?

HST's hitting the bank at Bromsgrove doing 80mph are often doing around 60mph at the top of the 1 in 37.5 at Blackwell. The Voyager logs from around 2012/2013 show speeds of around 70mph being achievable at Blackwell - the days when higher engine outputs were the norm. From Blackwell, the gradient eases to 1 in 291, and Barnt Green is on the other side of the summit on a 1 in 290 downgrade. Speeds approaching 90mph are achievable at Barnt Green with a clear run. But the Cross City Line services frequently cause signal checks!
Occasionally some extraordinary runs have been recorded, especially in the 1980's and 1990's before TPWS, onboard data recorder etc.
One such run from 1985 started the climb at Bromsgrove at a racy 96mph topping the bank at 76mph. In 1997 we have details of a run that went through Bromsgrove at 84mph hitting Blackwell at 74mph. Bart Green was passed at speeds of 87 and 89mph respectively.
For those specifically interested in HST performance over the years, The Railway Performance Society produced a booklet back in 2016 dedicated to 40 years of the HST's - with technical explanations of traction performance and examples of how performance has evolved due to changes in formations and route enhancements - with comparisons to older and more modern stock.

There is an electronic version available for members - £16 per year - and this allows unlimited access for a year to the full archive containing thousands of HST performance logs as well as other traction. UK, Europe and Worldwide.

 

[londonmidland]

Interesting! Thanks for that detailed reply.

 

[virgintrain1]

I recall Virgin Trains publicity stating 'sports car acceleration' - 0 to 60mph in 60 seconds for 220 and 70 seconds for 221s

Voyager Spec from the VTXC New Dawn CrossCountry: Dream to Reality magazine from May 2001.

 

[hexagon789]

Voyager Spec from the VTXC New Dawn CrossCountry: Dream to Reality magazine from May 2001.

That's very interesting because it shows the traction motors as being rated at 235kW, Platform 5 has them at 275kW which I always thought seemed too high

 

[hwl]

That's very interesting because it shows the traction motors as being rated at 235kW, Platform 5 has them at 275kW which I always thought seemed too high

235 adds up overall when you account for auxiliaries (hotel loads) and losses without any performance impact from derating that happen over decade after that document (which aligns with derating isn't performance impacting), 275 doesn't even before derating...

 

[hexagon789]

235 adds up overall when you account for auxiliaries (hotel loads) and losses without any performance impact from derating that happen over decade after that document (which aligns with derating isn't performance impacting), 275 doesn't even before derating...

Exactly, I didn't see how you could hope to get 737.6hp (550kW) out of the two motors per car when the engines are only fractionally more powerful at 750hp (559kW).

 

[37057]

Exactly, I didn't see how you could hope to get 737.6hp (550kW) out of the two motors per car when the engines are only fractionally more powerful at 750hp (559kW).

Also interesting how they get 750hp from 1800 rpm...

 

[Domh245]

Also interesting how they get 750hp from 1800 rpm...

That's what Cummins rate the engine for...

Rail | Cummins Inc.

Rating: 60 - 3300 hp (45-2460 kW) More than 70 years of experience in the rail market Over 13,000 Cummins rail engines in operation Wherever there’s advanced rail technology, you’ll find Cummins power. Under the floor on Europe’s high speed passenger trains, or fitted on 20 ton grinders in the...

cumminseurope.com

 

[37057]

That's what Cummins rate the engine for...

Rail | Cummins Inc.

Rating: 60 - 3300 hp (45-2460 kW) More than 70 years of experience in the rail market Over 13,000 Cummins rail engines in operation Wherever there’s advanced rail technology, you’ll find Cummins power. Under the floor on Europe’s high speed passenger trains, or fitted on 20 ton grinders in the...

cumminseurope.com

New ones maybe, old ones not so. 750hp @ 2100rpm on a CM500 HPI type QSK19 and I'm sure the calibration specs are the same for all three customers of Cummins for DMUs (Alstom, Bombardier & Siemens).

 

[hexagon789]

Also interesting how they get 750hp from 1800 rpm...

I've seen various sources state 1800 or 2100rpm. I've never been sure which is correct.

 

[37057]

Its possible that the engine is rated for 750hp @ 2100rpm but the traction system only demands a maximum throttle speed of 1800rpm due to the fact they're driving alternators rather than a turbos.

If that's the case, they must have an easier life under Voyagers than 180s/185s!

 

[hwl]

New ones maybe, old ones not so. 750hp @ 2100rpm on a CM500 HPI type QSK19 and I'm sure the calibration specs are the same for all three customers of Cummins for DMUs (Alstom, Bombardier & Siemens).

The specs aren't the same.
Voyagers and meridian are 1800rpm max and are effectively set up as 60Hz genset.

 

[37057]

The specs aren't the same.
Voyagers and meridian are 1800rpm max and are effectively set up as 60Hz genset.

But is it set up like that on the engine ECM or is it the traction control on the unit side that limits max speed?

 

[hwl]

But is it set up like that on the engine ECM or is it the traction control on the unit side that limits max speed?

Engine