Jump to content
 

HST 'racing' a new GWR set


Recommended Posts

This video (below) is produced by GWR and supposedly shows how much faster the acceleration is from one of their new sets compared to a HST. This is supposedly to show how much better they are.

 

Without getting into the rights and wrongs of this (opinion is split between the nice and comfortable, reliable and familiar HST and the new green credentials of the new sets), does anyone have any views on whether this is a fair test or whether the HST has not been driven to its full potential? I for one after travelling 10,000s miles on them have never seen one pull away this slowly when both PCs are working.

https://www.facebook.com/gwruk/videos/3394464530779763

 

Both trains will have their supporters, that's not in dispute- all I would like to know is whether this is a fair test or not.

 

Thanks.

Link to post
Share on other sites

HST  4500hp on 8 axles; 18.75t axle load

91 6300hp on 4 axles: 21t axle load.

800 (9 car) approx 6000hp on electric 4700hp diesel on 20 axles: 12.5t axle load.

 

On electric a 800 out accelerates both HST and 91 up to about 100mph (as expected for distributed motive power) after which (from GPS) the 800 acceleration flattens out and  dips below 91s.

On diesel I don't have too many comparable tracks but it is nothing special. I had a pair of 800/2 diverted via Lincoln due to a jumper and comparable to a Sprinter it was slower to line speed (may be driving style)

Link to post
Share on other sites

I seem to recall reading something a while ago that GWR HSTs had several power notches isolated, or drivers were instructed not to go above notch 5 which will make them seem sluggish.

That may have been changed by now, also what load are they comparing?Several of our ex LNER HSTs are running as 6 cars at present and seem pretty quick. When the same power cars were shifting 9 cars on East coast they were nowhere near as sprightly.

 

Edit: shoulda watched the bit of video first, d'oh, the HST is quite an old clip, so could be one running at notch 5 maximum.

Edited by great central
Add last paragraph
Link to post
Share on other sites

According to the 34A Facebook Kings Cross staff group, the new trains out-accelerate the HSTs by "quite a bit" but of course are far less comfortable. Their comments are from those who have driven on the ECML since the Deltic days.

  • Like 1
Link to post
Share on other sites

4 minutes ago, roythebus said:

According to the 34A Facebook Kings Cross staff group, the new trains out-accelerate the HSTs by "quite a bit" but of course are far less comfortable. Their comments are from those who have driven on the ECML since the Deltic days.

 

Can't disagree with that, watching them leave Grantham it's obvious they're a lot quicker on electric than anything else.

So far I've only sat on one for a couple of minutes, decided it was far from comfortable so went back to St Pancras for a Meridian, the next HST being nearly an hour later. 

Link to post
Share on other sites

2 hours ago, great central said:

 

Can't disagree with that, watching them leave Grantham it's obvious they're a lot quicker on electric than anything else.

So far I've only sat on one for a couple of minutes, decided it was far from comfortable so went back to St Pancras for a Meridian, the next HST being nearly an hour later. 

 

I have to say the driving on the GW HST was being a bit limp on the video. Compare that to a ECML HST from Newark, Grantham or Stevenage leaving on full bung.

 

However as others have said a turn of speed is nice to have - comfy seats essential. Missing out on a couple of trips to London every month being subjected to an Azuma is one of the things I am not missing with COVID. 

  • Like 1
  • Agree 1
Link to post
Share on other sites

15 hours ago, great central said:

I seem to recall reading something a while ago that GWR HSTs had several power notches isolated, or drivers were instructed not to go above notch 5 which will make them seem sluggish.

That may have been changed by now, also what load are they comparing?Several of our ex LNER HSTs are running as 6 cars at present and seem pretty quick. When the same power cars were shifting 9 cars on East coast they were nowhere near as sprightly.

 

Edit: shoulda watched the bit of video first, d'oh, the HST is quite an old clip, so could be one running at notch 5 maximum.

 

I think you'll find it's very difficult to go above notch 5 on an HST :huh:

Edited by DY444
  • Like 1
  • Agree 1
Link to post
Share on other sites

  • 5 weeks later...

Yes, as others have said, an 800 can out-pace anything else - but, only when on electric.

In that clip, theres not an overhead wire in site so the 800s clearly on diesel and that clip's clearly rigged!

 

On the climb through Chester-le-Street towards Durham

A 91 will manage, just about, the 115 linespeed

An HST would manage about 110

An 800 on diesel? Max out at about 101 then drop back for the 90 at Newton Hall virtually without having to shut off

Link to post
Share on other sites

On 02/12/2020 at 19:58, Bomag said:

HST  4500hp on 8 axles; 18.75t axle load

91 6300hp on 4 axles: 21t axle load.

800 (9 car) approx 6000hp on electric 4700hp diesel on 20 axles: 12.5t axle load.

 

On electric a 800 out accelerates both HST and 91 up to about 100mph (as expected for distributed motive power) after which (from GPS) the 800 acceleration flattens out and  dips below 91s.

On diesel I don't have too many comparable tracks but it is nothing special. I had a pair of 800/2 diverted via Lincoln due to a jumper and comparable to a Sprinter it was slower to line speed (may be driving style)

 

The 9-car 800s 3750hp on diesel - 5 x 750hp engines

 

Yes, even on electric the 800s 'acceleration' is only notable by it's absence once up to about 100mph.

The 91 on the other hand, while slow starting off, really gets itself into gear once you're up to about 60.  Approaching 125 you can still see the speedo needle moving and it would still keep on going, they were afterall designed for 140mph operation. So, overall the 91s only take a mile or two longer than the 800 in getting to 125.

 

Your experience of an 800 via Lincoln sounds probably about right

Link to post
Share on other sites

1 hour ago, Bomag said:

 

According to a few sources I have seen (including P5 combined) all engines on 800/801/802 are now rated at 940hp

 

I'm a bit out of touch but I thought that was only the GWR units and the others were still at 750.  I've also read that even where it has been uprated the engine management software keeps a very tight grip on it such that the maximum amount of power actually available is generally lower.

Link to post
Share on other sites

5 hours ago, DY444 said:

 

I'm a bit out of touch but I thought that was only the GWR units and the others were still at 750.  I've also read that even where it has been uprated the engine management software keeps a very tight grip on it such that the maximum amount of power actually available is generally lower.

 

I believe they were "unleashed" fairly early on after it was realised that keeping them at 750 increased the maintenance cycle and associated costs (remember every penny is counted by the DfT / Hitachi on those 800s) and because the 802s were proving to be faster. 

 

As for that video, yes, I and a few others who deal with HSTs all feel that said video was a cleverly designed piece of PR - mislead the public with an "Heres your old old train, look how much slower it is vs your Shiny, Fast, "Bullet Train" train". As others have already mentioned, the IET will have the advantage off the mark (any distributed traction unit will do that), but if you're putting it straight into highest power notch vs driving as gently as possible (in the HST) then it's even easier to make the IET look faster. 

Link to post
Share on other sites

1 hour ago, surfsup said:

As for that video, yes, I and a few others who deal with HSTs all feel that said video was a cleverly designed piece of PR - mislead the public with an "Heres your old old train, look how much slower it is vs your Shiny, Fast, "Bullet Train" train".

i.e. It's a lie.

  • Agree 1
Link to post
Share on other sites

9 hours ago, surfsup said:

 

I believe they were "unleashed" fairly early on after it was realised that keeping them at 750 increased the maintenance cycle and associated costs (remember every penny is counted by the DfT / Hitachi on those 800s) and because the 802s were proving to be faster. 

 

As for that video, yes, I and a few others who deal with HSTs all feel that said video was a cleverly designed piece of PR - mislead the public with an "Heres your old old train, look how much slower it is vs your Shiny, Fast, "Bullet Train" train". As others have already mentioned, the IET will have the advantage off the mark (any distributed traction unit will do that), but if you're putting it straight into highest power notch vs driving as gently as possible (in the HST) then it's even easier to make the IET look faster. 

 

I've now done some digging.  Usually reliable sources believe that the LNER bimode IETs remain at 750hp.

 

I don't think the IET in diesel being faster off the mark is anything to do with distributed traction.  Rather it's to do with design decisions as to how the available diesel power was to be deployed in the IET and the need to limit traction motor current in the HST power cars at low speed. 

 

The IET traction software was set up specifically to give fast acceleration from rest on diesel with the engine power being deliberately restricted above a certain speed.  By contrast the HST power cars have a system which deliberately restricts traction motor current up to a certain speed.  I can't remember the numbers but it's something like a max current of 1500A up to 35mph ish.  Or put another way the IET was deliberately set up to accelerate rapidly up to about 40mph on diesel and the HST was deliberately constrained.  This is why in original trim the IET took off quickly and then quickly ran out of puff and the HST did the opposite.  The increase to 940hp has made most difference to the IET diesel performance at higher speeds as you'd expect.

  • Informative/Useful 2
Link to post
Share on other sites

12 hours ago, surfsup said:

 

As for that video, yes, I and a few others who deal with HSTs all feel that said video was a cleverly designed piece of PR - mislead the public with an "Heres your old old train, look how much slower it is vs your Shiny, Fast, "Bullet Train" train". As others have already mentioned, the IET will have the advantage off the mark (any distributed traction unit will do that), but if you're putting it straight into highest power notch vs driving as gently as possible (in the HST) then it's even easier to make the IET look faster. 

 

I didn't get any sound in the video. This would have really helped to determine whether each train was being driven very hard. The HST certainly didn't look like it was being asked for much performance.

 

It reminds me of when the Pendolinos were bring introduced on the WCML. A Mk3 set hauled by a class 87 or 90 would always slow down several times during my journey home from London to MK, as if it was running on double yellows for a significant part of the journey. I used to hope for a trip when it wasn't held, just to see what it could really do. This never happened.

With a Pendolino running the same service, it usually seemed to get a clear run.

I was, & still am, convinced it was a deliberate ploy to skew figures & passenger opinions in favour of the newer trains.

Link to post
Share on other sites

1 hour ago, Pete the Elaner said:

It reminds me of when the Pendolinos were bring introduced on the WCML. A Mk3 set hauled by a class 87 or 90 would always slow down several times during my journey home from London to MK, as if it was running on double yellows for a significant part of the journey. I used to hope for a trip when it wasn't held, just to see what it could really do. This never happened.

With a Pendolino running the same service, it usually seemed to get a clear run.

I was, & still am, convinced it was a deliberate ploy to skew figures & passenger opinions in favour of the newer trains.

 

Seriously ? How do you think that would be arranged, ie for a loco-operated service not to have a clear run, whereas a Pendolino would ? 

 

Link to post
Share on other sites

31 minutes ago, caradoc said:

 

Seriously ? How do you think that would be arranged, ie for a loco-operated service not to have a clear run, whereas a Pendolino would ? 

 

 

I doubt there were lots of double yellows; it just felt like it.

 

The loco hauled sets definitely kept braking to check their speed & it was not just for normal line restrictions either, because they appeared to slow in different places. Linslade tunnel was particularly noticeable because taking the narrow single bore down fast at full speed in a Mk3A makes quite a roar.

It was another story when a Pendo was rostered for the same service. After accelerating through Wembley, it never seemed to slow appreciably until Denbigh Hall. I know EPS line speeds are higher, but not by as much as the services differed.

Link to post
Share on other sites

4 hours ago, Pete the Elaner said:

was, & still am, convinced it was a deliberate ploy to skew figures & passenger opinions in favour of the newer trains

That's the kind of conspiracy theory that would require so many people to be in on it that it wouldn't remain secret for long. Especially when most of those required to take part are train drivers, a group which often seems to prefer the old traction.

  • Agree 1
Link to post
Share on other sites

4 minutes ago, Zomboid said:

That's the kind of conspiracy theory that would require so many people to be in on it that it wouldn't remain secret for long. Especially when most of those required to take part are train drivers, a group which often seems to prefer the old traction.

 

I agree but...

The Mk3A sets consistently ran fast/slow/fast a the time..the Pendos maintained their speed. I used the services 5 days a week at the time. The difference was noticeable & consistent. It was a lot more than standard & EPS line speeds.

I would accept a better explanation if you have one?

Link to post
Share on other sites

I've not got much to offer there. They were in different paths I assume, so the chance of hitting a double yellow would be different on the LHCS compared to the Pendo, so it could actually be signals.

 

And the simple fact that EPS exists means that it's an apples to apples comparison, even if that doesn't fully explain the differences.

 

It would have been an LHCS timetable, so maybe the pendo could keep time at a constant 100 (or whatever), whilst the LHCS had to get to 110 to compensate for the fact that it also had to run at 80-90 for some sections whilst still keeping time?

Link to post
Share on other sites

22 minutes ago, Zomboid said:

I've not got much to offer there. They were in different paths I assume, so the chance of hitting a double yellow would be different on the LHCS compared to the Pendo, so it could actually be signals.

 

And the simple fact that EPS exists means that it's an apples to apples comparison, even if that doesn't fully explain the differences.

 

It would have been an LHCS timetable, so maybe the pendo could keep time at a constant 100 (or whatever), whilst the LHCS had to get to 110 to compensate for the fact that it also had to run at 80-90 for some sections whilst still keeping time?

 

It's not really clear which period is being referred to here.  There was quite a long period when pendos worked to the LHCS 110mph timings alongside the loco hauled sets and would gain time hand over fist just through acceleration and so coasting was quite common to avoid lots of hanging about waiting for platforms etc.  I remember one journey where, after a long delay at Hest Bank, a pendo gained 55 minutes on the LHCS timings between Lancaster and Euston all without exceeding 110mph. 

 

Having said that I don't remember loco hauled trains constantly slowing down in this period when pendos didn't.  There was a lot of engineering work though and so TSRs were common and the pendos were able to recover line speed very quickly compared with 87/90 hauled trains which was a very noticeable feature.

 

Edited by DY444
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...