• Our booking engine at tickets.railforums.co.uk (powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!

ScotRail HST Introduction - Updates & Discussion

Status
Not open for further replies.
43096

43096

On Moderation
Joined
23 Nov 2015
Messages
15,300
Stathern Jc said:
But how long should it take to get the hang of something that ought to be straightforward, and which you might expect to be part of the basic training before staff are allowed to take this stock out on the line??
Click to expand...
About 30 seconds tops to get the hang of it. It really couldn’t be any simpler.
 
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R

RailUK Forums

D

DannyMich2018

Member
Joined
19 Dec 2018
Messages
736
Any news on refurb set no 11? It's been a month now since the last one delivered. Sadly this program doesn't appear to be getting any quicker.
 
S

Steven_G

Member
Joined
5 Mar 2018
Messages
140
Let’s see how long before it’s in service.

A sign the quality of the refurb work has been maintained since last autumn.
 
I

InOban

Established Member
Joined
12 Mar 2017
Messages
4,221
I must admit I was surprised to see a Monday path. After all, it would have to have been completed on Friday, so would probably have come up today.
 
S

SC318250

Member
Joined
4 Jun 2011
Messages
617
Path in on Wednesday from Kilmarnock Brodies to Haymarket Depot. Shown as sprinter, but I guess this will be a HST coming from C4 overhaul?
 
Railperf

Railperf

Established Member
Joined
30 Oct 2017
Messages
2,942
Interesting to analyse performance of the HST's vs 170's on the Highland Main Line. The HST's are more than capable of maintaining line speed on the climbs - whereas the 170's struggle. Hence the linespeed profile seems to have been optimised for the 170's.

As an example HST's maintain 75mph from Dalwhinnie southbound to Drumochter summit, while the 170's top out at 65mph in that 2nd to 3rd gear change speed zone - often hunting between the two. So a HST gains 30 seconds on the climb - by being able to maintain line speed - which in reality could be 80 to 90mph with ease. In fact the linespeed 'downhill in the opposite direction to Dalwhinnie is 80/90SP. South of Drumochter - the 170's take advantage of the 80/90SP speed differential and claws back most of the lost time by running 10mph faster downhill.

Interestingly in the northbound direction the 170's are allowed 70mph thanks to a 60/70SP allowance - but here again they struggle - dropping as low as 55mph on that climb. Whereas the HST's can hold their 60mph allowance with ease.
On average it seems that HST's will gain at least 3/4 min on each station start due to the fast acceleration - but smarter braking on the 170's (possibly mitigated by the fact that HST's are running early and therefore drivers taking it easier on the brakes ) does seem to claw back some time - seemingly 15 to 20 seconds.

It does seem that to utilise the full potential of the HST's many of the existing line speed limits need to be tweaked to match the short HST acceleration profile where they were originally set to match a Class 170's acceleration profile. And when the 170's are fully loaded, they are even slower.
Be. interesting to see what tweaks if any are made to the speed limits along that route. I wonder how much a limiting factor for higher speeds is the extensive use of absolute block semaphore signalling used along vast stretches of line.
 
C

class26

Member
Joined
4 May 2011
Messages
1,125
Railperf said:
Interesting to analyse performance of the HST's vs 170's on the Highland Main Line. The HST's are more than capable of maintaining line speed on the climbs - whereas the 170's struggle. Hence the linespeed profile seems to have been optimised for the 170's.

As an example HST's maintain 75mph from Dalwhinnie southbound to Drumochter summit, while the 170's top out at 65mph in that 2nd to 3rd gear change speed zone - often hunting between the two. So a HST gains 30 seconds on the climb - by being able to maintain line speed - which in reality could be 80 to 90mph with ease. In fact the linespeed 'downhill in the opposite direction to Dalwhinnie is 80/90SP. South of Drumochter - the 170's take advantage of the 80/90SP speed differential and claws back most of the lost time by running 10mph faster downhill.

Interestingly in the northbound direction the 170's are allowed 70mph thanks to a 60/70SP allowance - but here again they struggle - dropping as low as 55mph on that climb. Whereas the HST's can hold their 60mph allowance with ease.
On average it seems that HST's will gain at least 3/4 min on each station start due to the fast acceleration - but smarter braking on the 170's (possibly mitigated by the fact that HST's are running early and therefore drivers taking it easier on the brakes ) does seem to claw back some time - seemingly 15 to 20 seconds.

It does seem that to utilise the full potential of the HST's many of the existing line speed limits need to be tweaked to match the short HST acceleration profile where they were originally set to match a Class 170's acceleration profile. And when the 170's are fully loaded, they are even slower.
Be. interesting to see what tweaks if any are made to the speed limits along that route. I wonder how much a limiting factor for higher speeds is the extensive use of absolute block semaphore signalling used along vast stretches of line.
Click to expand...

Of topic a little but there is an interesting article in February`s Modern Railways by Roger Ford (Captain Deltic) comparing an Azuma`s performance on the Highland main line to a HST . Despite the assurances given by the DAFT that distributed power would make up for lack of horse power not surprisingly the HST wins gaing 2 minutes between Inverness and Perth. It seems you cannot go against the laws of Physics afterall !
 
hexagon789

hexagon789

Veteran Member
Joined
2 Sep 2016
Messages
15,791
Location
Glasgow
Railperf said:
As an example HST's maintain 75mph from Dalwhinnie southbound to Drumochter summit, while the 170's top out at 65mph in that 2nd to 3rd gear change speed zone - often hunting between the two.
Click to expand...

They've only got two ;). Torque Convertor to ~70mph, Fluid Coupling above that, the issue is insufficient power to attain a high enough speed to change up onto the Fluid Coupling.
 
Railperf

Railperf

Established Member
Joined
30 Oct 2017
Messages
2,942
class26 said:
Of topic a little but there is an interesting article in February`s Modern Railways by Roger Ford (Captain Deltic) comparing an Azuma`s performance on the Highland main line to a HST . Despite the assurances given by the DAFT that distributed power would make up for lack of horse power not surprisingly the HST wins gaing 2 minutes between Inverness and Perth. It seems you cannot go against the laws of Physics afterall !
Click to expand...
Yes, this is the crazy situation. Scotrail want faster journeys between Glasgow /Edinburgh and Inverness. The short HST's have a higher power to weight ratio and are able to run faster which potentially can be used to shave up to 10 minutes off the journey. Ironically the LNER service will be a few minutes slower through the Highland section. At a time when they are spending billions upgrading the A9, you would have hoped that some investment on the highland main line would allow all services to be speeded up including freight. At least the Azuma's are able to use clean electric power all the way from Stirling to London. But it is a shame they weren't designed with a suitable power to eight ratio to meet the aspiration of faster Perth to Inverness journey times. The tourists won't mind because the views are amazing from the train - and you can enjoy a whiskey too.
 
Railperf

Railperf

Established Member
Joined
30 Oct 2017
Messages
2,942
hexagon789 said:
They've only got two ;). Torque Convertor to ~70mph, Fluid Coupling above that, the issue is insufficient power to attain a high enough speed to change up onto the Fluid Coupling.
Click to expand...
Really? I stand corrected lol.
 
I

InOban

Established Member
Joined
12 Mar 2017
Messages
4,221
InOban said:
That's what I had noticed. We'll see if it runs!
Click to expand...
Bingo! It exists.
I'm a bit puzzled by the route. It's pathed round by the Sub, so it ends up with multiple reversals at Haymarket to access the depot. It would have been much easier to send it through Waverley, as they did last time.
And there's a strange entry at Grantshouse loop!
 
R

RLBH

Member
Joined
17 May 2018
Messages
962
InOban said:
Bingo! It exists.
I'm a bit puzzled by the route. It's pathed round by the Sub, so it ends up with multiple reversals at Haymarket to access the depot. It would have been much easier to send it through Waverley, as they did last time.
And there's a strange entry at Grantshouse loop!
Click to expand...
Alarming if true! I do hope that the driver's dinner order isn't so large it needs shunting into the formation? :lol:
 
J

jimm

Established Member
Joined
6 Apr 2012
Messages
5,231
class26 said:
Of topic a little but there is an interesting article in February`s Modern Railways by Roger Ford (Captain Deltic) comparing an Azuma`s performance on the Highland main line to a HST . Despite the assurances given by the DAFT that distributed power would make up for lack of horse power not surprisingly the HST wins gaing 2 minutes between Inverness and Perth. It seems you cannot go against the laws of Physics afterall !
Click to expand...

He was actually writing about the section of the journey from Inverness up to Slochd summit, not the full run to Perth, and added "does two minutes lost on the climb to Slochd summit so early in the journey matter? Not really."
 
hexagon789

hexagon789

Veteran Member
Joined
2 Sep 2016
Messages
15,791
Location
Glasgow
Railperf said:
Really? I stand corrected lol.
Click to expand...

Yes, 170s have a two-stage transmission. 185s have three, perhaps a confusion with those?

Regardless, though the HST's performance is far superior of course as you said, all we need is a timetable to take advantage of that but that's some time away yet I fear.
 
Speed43125

Speed43125

Member
Joined
20 Jul 2019
Messages
1,137
Location
Dunblane
hexagon789 said:
Yes, 170s have a two-stage transmission. 185s have three, perhaps a confusion with those?

Regardless, though the HST's performance is far superior of course as you said, all we need is a timetable to take advantage of that but that's some time away yet I fear.
Click to expand...
The timetable at current is designed so even a crush loaded 158 can just about keep up (if you ignore huge dwell times perhaps), things are moving in the right direction, but I wonder when we will reach a stage when we can be certain of at least certain paths being HSTs
 
Railperf

Railperf

Established Member
Joined
30 Oct 2017
Messages
2,942
jimm said:
He was actually writing about the section of the journey from Inverness up to Slochd summit, not the full run to Perth, and added "does two minutes lost on the climb to Slochd summit so early in the journey matter? Not really."
Click to expand...
It might not matter to him..as he does not use the line on a regular basis. That is just his opinion. If his local train service started to be slowed down because the trains were slower..i am sure it would not be met positively. This is the man that champions the Deltic loco's - trains that were faster than the ones they replaced. Regular users of the Highland Main line want faster and more frequent trains. Losing two minutes to Schlod is just the start. There are further time losses on the way to Perth. Every time the Azuma starts from a station or has to accelerate from a low speed restriction - or power up a gradient..it is losing time compared to the trains it replaced and even more time to the shorter HSTs. Thankfully the timetable is not currently too demanding with plenty of recovery time and pathing allowances to eat in to.
 
Status
Not open for further replies.

Top