Avanti IET Speeds

[LNW-GW Joint]

Avanti's 390s also do not use their maximum power at low speeds, as has been reported on here before, as part of the driving technique.
I think the same might apply to TPE's 397s.
There will also be a difference between the performance of the all-electric and bi-mode 80x sets under electric because of the weight difference.
Off electric, the bi-modes will not need anything more than 90mph on Avanti routes.

 

[Railperf]

The whole situation with diesel engine "uprating" (/ceiling removal) is far too complex for me to keep up with!



You've mistaken peak acceleration for acceleration. 80x are designed to hold ~0.75ms/s^2 up to about 45kph, before then tapering off towards higher speeds (which when you plot the power required gives a lovely straight line from about 45kph onwards!)

This shows the acceleration profile that IEP units are supposed to achieve (although when you run the maths, they do slightly better as this profile gets them to 200kph in about 4:20 compared to the timed 3:00
View attachment 89311

This curve is the original DfT specificationnfor performance - which the early GWR 800s were more or less achieving.
GWR's own fleet of Class 802's came into service with an identical traction spec but were much faster as they didn't have to meet the DfT spec.
So it became clear that DfT-ordered units were being 'reigned back artificially.
Since then the 'electric' performance across the GWR fleets has been de-restricted to match the 802's. LNER trains also seem to have been de restricted.. except when in diesel mode.

 

[Ianno87]

So it became clear that DfT-ordered units were being 'reigned back artificially.

Not sure it "became clear"- it was always known in the contract.

 

[Domh245]

Since then the 'electric' performance across the GWR fleets has been de-restricted to match the 802's. LNER trains also seem to have been de restricted.. except when in diesel mode.

Ah, that would explain the discrepancy! I didn't know that they'd been through that de-restriction

 

[Railperf]

Those will be maximum acceleration rates, there's no way an 80x makes 125 in under 1 minute 20.

An 801 takes just over 3 min 0 to 125mph.

9

They're fairly sluggish. Up to a fair speed a 350 will easily pull ahead.

Yes..the 390's acceleration is stronger in the upper speed range.

Is the acceleration of an IET really that much quicker than a 390

No.

There will also be a difference between the performance of the all-electric and bi-mode 80x sets under electric because of the weight difference.

Hardly any difference between a bimode 800 and an all electric 801 to 125mph - maybe 10 to 15 seconds - which equates to just a few seconds in terms of time to distance

 

[bengley]

Avanti's 390s also do not use their maximum power at low speeds, as has been reported on here before, as part of the driving technique.
I think the same might apply to TPE's 397s.
There will also be a difference between the performance of the all-electric and bi-mode 80x sets under electric because of the weight difference.
Off electric, the bi-modes will not need anything more than 90mph on Avanti routes.

That doesn't apply to 397s

 

[Railperf]

That doesn't apply to 397s

So far the 397's performance characteristics to 110mph seem almost identical to an IET. It remains to be seen how good their acceleration is from 110 to 125mph.
As I say, - if you look at the time taken to get to around 2.4 miles from rest, then a Class 397 seems to pip the Class 801 by a second or two, a Class 350 would be a further 8 seconds behind, with the 390 coming up the rear around 20 secs behind the 397/801.
The 390's hit 110mph in 3 miles, and 125mph in just over 4 miles, so from 3 miles they are reigning in the 350's and 110mph limited 397's , but remain around 20 seconds behind the 801.

I think people are forgetting regarding the WCML tile, that faster acceleration was one of the benefits of using a Class 390 over the loco hauled stock. It wasn't all about tilt. Millions were spent on remodelling junction layouts etc to allow faster speeds regardless of whether the trains tilted or not.

And that's why calls for Class 90's and loco hauled stock to return to the WCML are out of touch with the reality. 100mph limited Class 745's are producing superior performances to 110mph Class 90's on the GEML in dry and wet weather - even in cases where the 90's have been recorded running well over 100mph.

I'm sure the experts would have modelled the benefits of even faster accelerating non-tilt train journey time improvements. Clearly the benefits of 125mph running are only gained over longer distances - so EPS speeds were designed around lengths of track that could offer long stretches of continuous 125mph running.

The alternative would have been lots of shorter sections of running at 125mph punctuated by lower speed restrictions as low as 75mph. Having to keep accelerating up to speed and braking again wastes a lot of energy and increases wear and tear on the brakes - for a much lower gain in journey times.

Clearly it would have been cheaper to have ordered a fleet of non tilt 125mph electric trains than the 390's, but the timetable would have been slower, the running costs higher. The improved journey times gained by 125mph tilt and higher frequency have attracted more passengers = more revenue. You certainly would not have been able to offer London to Glasgow in 4h15mins with a non-tilting 125mph train. And as has been noted on other threads, the design speed was higher than that - 140mph.

 

[hexagon789]

An 801 takes just over 3 min 0 to 125mph.

Which is a good bit more than >80 seconds!

 

[Railperf]

I always wonder why Bushey curve was never raised to 125mph EPS speeds. I suspect the proximity to Watford tunnels limited to 115mph for aerodynamic reasons meant trains on the down main would have to start slowing anyway.. And the lower speed equals less track wear.

 

[Boodiggy]

I always wonder why Bushey curve was never raised to 125mph EPS speeds. I suspect the proximity to Watford tunnels limited to 115mph for aerodynamic reasons meant trains on the down main would have to start slowing anyway.. And the lower speed equals less track wear.

I am sure it was to do with the bridge at Watford south junction that was replaced a few years ago. As the junction has also been replaced I can’t see why it can’t. I know the OLE in the tunnel needs work for 125mph running.

 

[Ianno87]

I am sure it was to do with the bridge at Watford south junction that was replaced a few years ago. As the junction has also been replaced I can’t see why it can’t. I know the OLE in the tunnel needs work for 125mph running.

The tunnel aerodynamics will still be limiting.

If you solved the curve it's be an extra, what, half mile or so of EPS running instead of 115mph? Makes 2 seconds difference, tops.

 

[Boodiggy]

The tunnel aerodynamics will still be limiting.

If you solved the curve it's be an extra, what, half mile or so of EPS running instead of 115mph? Makes 2 seconds difference, tops.

Yep the aerodynamics will be an issue too.
The 115 is EPS, PS is 110 still..
The 110mph is from 15m20ch on the DF. Not much to be saved and that is why nothing has been done... the 110mph section is much shorter on the UF.
I am sure if it was planned it would be done at a time like Easter when part of the North Junction goes back in.

 

[gimmea50anyday]

LNER's 800s won't hit 125mph on diesel AFIAK (at least, not without the aid of gradients!)

Neither will TPEs 802s. Best I have seen is 122 at Hutton Bonville and that was without stopping at Northallerton. It had took from York that far to get to that speed.

IETs aren’t sluggish to accelerate, not on electric anyway. Diesel powered on the other hand they will shift initially but there just isn’t enough power above 110, acceleration out of Durham is certainly noticeable when using the different power modes (on electric the motors change pitch before Nevilles Cross Cutting, on diesel after) and can seem like a crawl on the ECML north of York. having said that running at 110 compared to 125 doesn’t really make much difference as far as TPE services are concerned, but that’s probably more down to the frequent stop nature of TPE compared to LNER and sitting awaiting time at Darlington and Durham.

 

[Nym]

Neither will TPEs 802s. Best I have seen is 122 at Hutton Bonville and that was without stopping at Northallerton. It had took from York that far to get to that speed.

IETs aren’t sluggish to accelerate, not on electric anyway. Diesel powered on the other hand they will shift initially but there just isn’t enough power above 110, acceleration out of Durham is certainly noticeable when using the different power modes (on electric the motors change pitch before Nevilles Cross Cutting, on diesel after) and can seem like a crawl on the ECML north of York. having said that running at 110 compared to 125 doesn’t really make much difference as far as TPE services are concerned, but that’s probably more down to the frequent stop nature of TPE compared to LNER and sitting awaiting time at Darlington and Durham.

I can confirm TPE's 802s will hit 125mph on diesel. And yes, I have been one one that hit this speed on Diesel.

 

[The Planner]

I am sure if it was planned it would be done at a time like Easter when part of the North Junction goes back in.

May Bank Holiday for that. Rest of Watford North is 2022.

 

[Boodiggy]

May Bank Holiday for that. Rest of Watford North is 2022.

Yep - shame with the access a bit more wasn’t being done...

 

[hexagon789]

Neither will TPEs 802s. Best I have seen is 122 at Hutton Bonville and that was without stopping at Northallerton. It had took from York that far to get to that speed.

IETs aren’t sluggish to accelerate, not on electric anyway. Diesel powered on the other hand they will shift initially but there just isn’t enough power above 110, acceleration out of Durham is certainly noticeable when using the different power modes (on electric the motors change pitch before Nevilles Cross Cutting, on diesel after) and can seem like a crawl on the ECML north of York. having said that running at 110 compared to 125 doesn’t really make much difference as far as TPE services are concerned, but that’s probably more down to the frequent stop nature of TPE compared to LNER and sitting awaiting time at Darlington and Durham.

Pretty sure the 802s can comfortably manage 125 on diesel as can GWR's 800s, only LNER 800s won't.

I can confirm TPE's 802s will hit 125mph on diesel. And yes, I have been one one that hit this speed on Diesel.

That was my understanding, the RPS probably have more of the details though.

 

[73128]

Which they won't be using much at all if the plan remains to keep them on London-Birmingham and London-Chester/Shrewsbury!

Isn't it Liverpool (with its new half hourly service) and Chester/Shrewsbury

 

[Domh245]

Isn't it Liverpool (with its new half hourly service) and Chester/Shrewsbury

Yes apparently. @gka472l mentioned this earlier in the thread as well, although it still doesn't really change the point I was making as they'll still be avoiding Wolves-Stafford unless this second Liverpool service is routed via Birmingham?

 

[73128]

Yes apparently. @gka472l mentioned this earlier in the thread as well, although it still doesn't really change the point I was making as they'll still be avoiding Wolves-Stafford unless this second Liverpool service is routed via Birmingham?

Agreed. I believe that it's going via the Trent Valley too, so avoiding that stretch as well.

 

[hexagon789]

Isn't it Liverpool (with its new half hourly service) and Chester/Shrewsbury

Isn't it both?

 

[gimmea50anyday]

I can confirm TPE's 802s will hit 125mph on diesel. And yes, I have been one one that hit this speed on Diesel.

Pretty sure the 802s can comfortably manage 125 on diesel as can GWR's 800s, only LNER 800s won't.


That was my understanding, the RPS probably have more of the details though.

How about first hand experience as I sign and work 802s on a daily basis?

802s will NOT hit 125 on diesel. And I am very certain every single member of staff out of my depot who work them on a daily basis will agree with me. And 802208 on 2 motor cars cannot hit 125 either and that IS on electric!

But of course being staff who actually work the trains I don’t know the facts. I’m only a tail lamp after all...

 

[Nym]

802201 and 802202 have hit 125mph on Diesel between Doncaster and Peterborough.

 

[gimmea50anyday]

No doubt helped by stoke bank but that’s cheating!

 

[hexagon789]

How about first hand experience as I sign and work 802s on a daily basis?

802s will NOT hit 125 on diesel. And I am very certain every single member of staff out of my depot who work them on a daily basis will agree with me. And 802208 on 2 motor cars cannot hit 125 either and that IS on electric!

But of course being staff who actually work the trains I don’t know the facts. I’m only a tail lamp after all...

There was no need to be quite so snarky - it's pointless arguing with you so let's leave it at that

 

[Energy]

How about first hand experience as I sign and work 802s on a daily basis?

802s will NOT hit 125 on diesel. And I am very certain every single member of staff out of my depot who work them on a daily basis will agree with me. And 802208 on 2 motor cars cannot hit 125 either and that IS on electric!

But of course being staff who actually work the trains I don’t know the facts. I’m only a tail lamp after all...

TPE (I'm assuming thats you're operator by the mention of 802208) go over the hilly pennines which will undoubtably slow the train down more than flat land, I would imagine the 802s can get to 125mph, just on flatter land and at a push on diesel.

 

[greatvoyager]

TPE (I'm assuming thats you're operator by the mention of 802208) go over the hilly pennines which will undoubtably slow the train down more than flat land, I would imagine the 802s can get to 125mph, just on flatter land and at a push on diesel.

Makes sense.

 

[Ianno87]

TPE (I'm assuming thats you're operator by the mention of 802208) go over the hilly pennines which will undoubtably slow the train down more than flat land, I would imagine the 802s can get to 125mph, just on flatter land and at a push on diesel.

None of the trans pennine main line is even close to 125mph line speed.

The only areas that can be attained is York-Newcastle-Edinburgh.

 

[notadriver]

Makes sense.

I can confirm on the level racing track between York and Darlington that an 802 on diesel can reach 122 mph.

 

[Railperf]

802201 and 802202 have hit 125mph on Diesel between Doncaster and Peterborough.

It's well known an 800/802 will do 125mph downhill in diesel mode. The GWR variants were able to reach 125mph eventually on the up main line downhill (appx 1 in 750), but not on the down.
But as stated earlier, they will NOT do 125mph on level track in diesel mode.

I'm struggling to understand what 125mph diesel running has has to do with Avanti, because the only stretches of diesel line that the Avanti bi-modes will work are 90mph maximum speed - well within the diesel capabilities. If Crewe to Chester and Holyhead were to be upgraded to 100/110mph, the bi-modes would cope okay.

I can confirm on the level racing track between York and Darlington that an 802 on diesel can reach 122 mph.

I guess they could technically reach 125mph if the full 940hp per engine were available at that speed. Shame the engines are ramped down to around 85% at that road speed.

No doubt helped by stoke bank but that’s cheating!

Not really. Network rail installed most of the 125mph sections on the Midland Main Line on reasonably level or downhill track to model where the 222's would best achieve and sustain it.

I can confirm on the level racing track between York and Darlington that an 802 on diesel can reach 122 mph.

Looking at a few Class 802 logs recorded before lockdown on the down main between York and Darlington and comparing this with a Class 185 run i recorded in 2019. A Class 185 can be anything from 20 to 35 seconds faster than an 802 to Beningborough. The quickest Class 802 run was level with the 185 by Pilmoor and had gained a minute over the 185 by Otterington due to 119mph running, while the slowest was only 20 seconds ahead at that point. Maximum speeds varied from 114 to 119mph.

Between Darlington and Durham, the 185's are slightly faster due to their better acceleration to 100mph in-spite of the 802's being able to get to 108mph maximum on that stretch. Plus the 185's get a quicker start from Darlington as they are only 3-cars. The 5-car 802's have to wait for the remaining two cars to exit the speed restricted turnouts.

Oh and just in case you are wondering how a Class 801 compares from York, it was two minutes quicker to Otterington compared to the 'diesel' 802 running at 119mph. Both clear runs with NO TSR's.
And onwards from Darlington to Durham, the 801 gained a lead of 90 secs over the 185 - itself quicker 20 secs faster than the diesel 802.

Really no point running 802's much over 100mph as their acceleration is awfully slow - much worse from 100mph to 125mph than an HST - but useful in an emergency - loss of OLE power - pantograph troubles etc.