Grand Central choosing 90s over 91s

[DorkingMain]

Apologies if this has already been addressed elsewhere.

What was the reasoning behind Grand Central choosing Class 90 locomotives rather than Class 91?

 

[43096]

Apologies if this has already been addressed elsewhere.

What was the reasoning behind Grand Central choosing Class 90 locomotives rather than Class 91?

The paths they have are 110mph and as a 90 is faster accelerating than a 91 it makes sense. In addition, hiring 90s is an internal DB transaction (at least until Arriva is spun off) which is beneficial to the DB group.

 

[Ianno87]

Class 90s accelerate better and the 125mph top speed of the 91s cannot generally be used anyway since speeds over 110mph are only (usually) for tilting stock

 

[Royston Vasey]

And the 90s can be maintained alongside the red ones by Crewe Electric TMD

 

[hwl]

Arriva effectively paying for some of DB's unservicable 90s to be fully refurbished.

 

[LNW-GW Joint]

The class 90 fleet has a future, class 91s don't, unless somebody chooses to lease a decent number of them.
Otherwise maintenance costs for a handful of locos become prohibitive.

 

[mackeral1234]

Class 90 have been used since the late 80s - InterCity/Virgin/RfD/EWS/RES/DB. So they would not need any new arrangement as the 91s may not be approved for the WCML.

 

[Clarence Yard]

It's quite simple.

The boss at GCR used to maintain the cl.91 fleet in a previous life and knows them only too well.
The 91 fleet is expensive to run and you need well trained staff, experienced in their ways, to maintain them.
91's will need to go through all the usual route compatibility and clearance procedures, unlike the 90's.
90's will do the job just as well and are less expensive.
DB have some spare 90's.

 

[hexagon789]

The RPS suggests that in spite of the oft-stated view that a 90 is faster accelerating than a 91, the difference is not as significant as it might first appear.

 

[Railperf]

The RPS suggests that in spite of the oft-stated view that a 90 is faster accelerating than a 91, the difference is not as significant as it might first appear.

Especially on wet rails!! I would have thought though that the planned upgrading of some WCML non EPS limits from 110mph to 125mph would have made a 125mph loco potentially more useful.

 

[mmh]

Especially on wet rails!! I would have thought though that the planned upgrading of some WCML non EPS limits from 110mph to 125mph would have made a 125mph loco potentially more useful.

Is there any source for planned 125 non-EPS running other than rumour?

As ever, it's worth pointing out that there are plenty of EPS speed differentials which aren't 110/125.

 

[DB]

The RPS suggests that in spite of the oft-stated view that a 90 is faster accelerating than a 91, the difference is not as significant as it might first appear.

91s shift above about 60mph, but are really slow accelerating below that.

 

[hexagon789]

Especially on wet rails!! I would have thought though that the planned upgrading of some WCML non EPS limits from 110mph to 125mph would have made a 125mph loco potentially more useful.

I remembered yourself mentioning that before, dispelling the myth over a significant difference between them. I think you said that to 110 they are both about 5 mins 30 or something? Can't quite remember.

91s shift above about 60mph, but are really slow accelerating below that.

Presumably because of the difference in maximum against continous power outputs. The 90 can produce up to 7,860hp, but continously only 5,000.

The 91 can produce up to 6,300hp and 6,090 continuous, so presumably the higher continous output means they have more grunt at higher speeds but the lower maximum output affects accelerating from a stand.

 

[Ianno87]

Especially on wet rails!! I would have thought though that the planned upgrading of some WCML non EPS limits from 110mph to 125mph would have made a 125mph loco potentially more useful.

Aren't those planned areas generally north of Preston?

 

[Bald Rick]

I would have thought though that the planned upgrading of some WCML non EPS limits from 110mph to 125mph would have made a 125mph loco potentially more useful.

“Planned” is rather too strong a word there. “Potential” is about the best that can be attached to that proposal at present. Which then makes the use of 90s rather sensible. Why would you want a small sub-fleet of locomotives that have never been used (and more importantly, maintained) on the WCML on the off chance that at some point in the medium to long term future some parts of the line might be upgraded for higher speeds if A N Other pays for it?

 

[43096]

Presumably because of the difference in maximum against continous power outputs. The 90 can produce up to 7,860hp, but continously only 5,000.

The 91 can produce up to 6,300hp and 6,090 continuous, so presumably the higher continous output means they have more grunt at higher speeds but the lower maximum output affects accelerating from a stand.

Gearing makes a difference as well, with the 91s being 140mph geared it's a greater differential from the 110 of the 90s than if they were 125mph geared.

 

[CW2]

I think the eventual aim of raising the non-tilt speed limits on the WCML is driven by the need for HS2's non-tilting trains to maintain competitive schedules north of Crewe. There's probably a strong business case for that, whereas any changes south of Crewe are as yet unproven and unfunded.

 

[hexagon789]

Gearing makes a difference as well, with the 91s being 140mph geared it's a greater differential from the 110 of the 90s than if they were 125mph geared.

Very true, but the gearing does mean that the 91 still has its turn of speed to come at 110mph while the gearing is beginning to hold the 90 back.

 

[The Planner]

Is there any source for planned 125 non-EPS running other than rumour?

As ever, it's worth pointing out that there are plenty of EPS speed differentials which aren't 110/125.

Yes, there is a large amount of work being done in the background. Don't expect 125 non EPS in large amounts, it will be a lot of 115 or 120.

I think the eventual aim of raising the non-tilt speed limits on the WCML is driven by the need for HS2's non-tilting trains to maintain competitive schedules north of Crewe. There's probably a strong business case for that, whereas any changes south of Crewe are as yet unproven and unfunded.

All the work is being done on the south of the route so 805/7 can take advantage initially.

 

[hexagon789]

All the work is being done on the south of the route so 805/7 can take advantage initially.

Slightly OT, but do you know if they are still doing anything north of Preston with a view to increasing non-EPS speeds?

 

[The Planner]

Slightly OT, but do you know if they are still doing anything north of Preston with a view to increasing non-EPS speeds?

It hasn't gone away but it is no way as advanced.

 

[Railperf]

Gareth Dennis reporting on Twitter that the work to increase non EPS speed limits is due to be completed by the end of the year..even though the delivery date keeps slipping.

https://twitter.com/railperf/status/1303626631467151360?s=20

 

[swt_passenger]

New thread in general discussion reports the GC Blackpool service has been abandoned :

Grand Central cancels plans to run London - Blackpool service

The railway rumour police will probably not like this one but I am hearing the operation is being abandoned and staff who were at Blackpool are being made redundant.... anyone heard any more? Edit - 1852, confirmed, seen an email the union are passing around on WhatsApp.

www.railforums.co.uk

Probably best that all discussion takes place there...

 

[hexagon789]

It hasn't gone away but it is no way as advanced.

Thanks, be interesting to see what they manage in due course

 

[Bald Rick]

Gareth Dennis reporting on Twitter that the work to increase non EPS speed limits is due to be completed by the end of the year..even though the delivery date keeps slipping.

https://twitter.com/railperf/status/1303626631467151360?s=20

Mr Dennis is woefully misinformed. The initial study work being done by Avanti might be done by the end of the year, but that’s not even the end of the beginning, to quote Churchill.

 

[Railperf]

Mr Dennis is woefully misinformed. The initial study work being done by Avanti might be done by the end of the year, but that’s not even the end of the beginning, to quote Churchill.

Who is commissioning the study for line speed improvements North WCML? I would have thought TPE as they were testing their trains at 125mph there?

 

[Bald Rick]

Who is commissioning the study for line speed improvements North WCML? I would have thought TPE as they were testing their trains at 125mph there?

AIUI, no one, yet. Certainly not TPE.

 

[The Planner]

Who is commissioning the study for line speed improvements North WCML? I would have thought TPE as they were testing their trains at 125mph there?

HS2 have had a bit of look at it, but it hasn't progressed anywhere in the last couple of years.