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Porterbrook Cl.769 'Flex' trains from 319s, initially for Northern

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Roger B

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a_c_skinner said:
They could always set off from Southport and have a whip round for diesel en route. More seriously all this trouble for a handful of units makes no sense, especially now the 319s are going.
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I share your frustration about the time it's taking to get them in service - I just don't get it. How hard can it be? But then, I'm not familiar with all the issues they're having to overcome, and I daresay there's a bunch of extremely talented and committed people who've gone above and beyond to get us to this point, and are itching to get the 769s into service.

And I'd maybe agree about whether it's worth the trouble if it were for just a handful of trains. But even if the 769s only operate for a few years, it'll help reduce diesel exhaust in Manchester. And there'll be the South Wales and Berkshire / Sussex sets in due course. The bigger prize is that hopefully Porterbrook are learning more all the time, some of which may be transferable. I've seen speculation about 350 bi-modes - now they would be something. I've not been able to find a separate thread for these - is there one? And with battery technology progressing all the time, there may also be room for battery bi-modes for 'proper' trains, rather than LU cast-offs.

The railway has to be de-carbonised, for the railways to play their part in getting to UK to being carbon-neutral - to make the railways the environment-friendly option. To get the public, the pressure groups, the politicians, the people who make investment decisions on board. For the railways to be seen as part of the solution, not the problem, as far as CO2 is concerned. Could result in big wins for the railway - but do great damage if the railways are judged to have got it wrong.
 
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37201xoIM

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Fair comments all, and I will admit I've never been a fan of this project. However, given where we are with (as yet) still no government commitment to electrification, a Northern fleet an order of magnitude smaller than it needs to be (the vast majority of the shortfall being diesel trains), and a near-absence (not complete, I know!) of diesel trains available now, one sensible option could well be to convert a significant number of additional 319s into 769s, even if many might rarely see the OLE. That is of course IF the 769s already produced can prove themselves in service!

That's alongside other (not mutually exclusive) interventions, including reprieving Pacers further.

Yes, it's crazy - but we are in a crazy situation, and it may be the least crazy if there is to be any alleviation of the rolling-stock crisis in the North.
 
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Roger B

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37201xoIM said:
Fair comments all, and I will admit I've never been a fan of this project. However, given where we are with (as yet) still no government commitment to electrification, a Northern fleet an order of magnitude smaller than it needs to be (the vast majority of the shortfall being diesel trains), and a near-absence (not complete, I know!) of diesel trains available now, one sensible option could well be to convert a significant number of additional 319s into 769s, even if many might rarely see the OLE. That is of course IF the 769s already produced can prove themselves in service!

That's alongside other (not mutually exclusive) interventions, including reprieving Pacers further.

Yes, it's crazy - but we are in a crazy situation, and it may be the least crazy if there is to be any alleviation of the rolling-stock crisis in the North.
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Not either/or, but both. Let the North have its cake and eat it. Yes, get some more bi-modes in as a short-term measure. And at the same time get a rolling programme of electrification going, filling in the gaps, aiming for network coverage. They've been doing infill electrification elsewhere for decades (a recent example being the GOBLIN line) - why not here as well?

They could do the 'easy' bits first (stretches of the CLC?), and then come back for the more challenging sections (like the tunnels Chapel-en-le-Frith and Dove Holes) later - with bi-modes every mile electrified reduces the amount of diesel burnt. It seems crazy that over 50 years after the 25kV wires reached Piccadilly that there are still so many diesels running around.
 
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plugwash

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Roger B said:
And I'd maybe agree about whether it's worth the trouble if it were for just a handful of trains. But even if the 769s only operate for a few years, it'll help reduce diesel exhaust in Manchester. And there'll be the South Wales and Berkshire / Sussex sets in due course. The bigger prize is that hopefully Porterbrook are learning more all the time, some of which may be transferable. I've seen speculation about 350 bi-modes - now they would be something. I've not been able to find a separate thread for these - is there one?
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Porterbrook has proposed battery conversions of the class 350s, https://www.railforums.co.uk/threads/class-350-batteryflex.171906/

If the rumors about the exhaust system causing massive delays due to re-testing requirements for emissions certification are true, then I can see it creating further pressure for future conversion projects to use power sources other than diesel (most likely battery, but maybe also hydrogen).
 
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AM9

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plugwash said:
Porterbrook has proposed battery conversions of the class 350s, https://www.railforums.co.uk/threads/class-350-batteryflex.171906/

If the rumors about the exhaust system causing massive delays due to re-testing requirements for emissions certification are true, then I can see it creating further pressure for future conversion projects to use power sources other than diesel (most likely battery, but maybe also hydrogen).
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The delay in re-certifying the train with a modified exhaust system was a problem because there is always demand for test house services. The original testing would have been in the programme from the design start. You are right about future novel traction systems though. High pressure hydrogen has a whole new set of safety and environmental issues that need clearance.
 
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Grannyjoans

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The problem with using the 769s on routes which don't see much electrified lines is fuel capacity. They really don't have much fuel capacity. I'm not sure what capacity the tanks are but I believe it is only around 400 litres, about half that of a 142 ?
 
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a_c_skinner

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How does that work out for range? (Googled it, what little there is says 500miles or comparable with 150s)
 
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37201xoIM

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Grannyjoans said:
The problem with using the 769s on routes which don't see much electrified lines is fuel capacity. They really don't have much fuel capacity. I'm not sure what capacity the tanks are but I believe it is only around 400 litres, about half that of a 142 ?
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Good grief, I did not know that! That is risible - and a potential killer. Was reading (here: https://www.railwaygazette.com/uk/w...tent=&utm_campaign=RBUKnewsletter- 05/03/2020) that in Wales they are apparently proposing to run them on the Rhymney line, almost entirely away from wires.

Roger B said:
They could do the 'easy' bits first (stretches of the CLC?), and then come back for the more challenging sections (like the tunnels Chapel-en-le-Frith and Dove Holes) later
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There's nowt difficult about wiring tunnels! Remember that a lot of OLE pioneers were in the Alps. And these days things like contact bars make it even easier. "Discontinuous electrification" has been largely debunked...
 
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JN114

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a_c_skinner said:
How does that work out for range? (Googled it, what little there is says 500miles or comparable with 150s)
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150 range is 1500mi for us...

All we’ve been told thus far at GW is that it’ll be less than the 16x which are 1200mi. All the North Downs multi-day diagrams have been brought down to under 1000mi in the recent TT change, so that’d be where I put my chips.

Remember that although the tanks on the 769s are smaller:-

1) The engines are much more modern and economical than “traditional” DMU engines.

2) The engines are purely being used to generate electrical power. Not only is that significantly more efficient than actually driving the wheels with the engine; but it’s a very different duty cycle, and thus fuel consumption through the engine.
 
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37201xoIM

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JN114 said:
2) The engines are purely being used to generate electrical power. Not only is that significantly more efficient than actually driving the wheels with the engine; but it’s a very different duty cycle, and thus fuel consumption through the engine.
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I know 15X slushboxes are not great, but is that true? Diesel-electric is for units generally less efficient than direct mechanical drive (as on 172, 195 etc.) - but I would have guess about the same as diesel-hydraulic? But d-e does generally involve extra weight.

Am not an engineer, mind!
 
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Roger B

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37201xoIM said:
I know 15X slushboxes are not great, but is that true? Diesel-electric is for units generally less efficient than direct mechanical drive (as on 172, 195 etc.) - but I would have guess about the same as diesel-hydraulic? But d-e does generally involve extra weight.

Am not an engineer, mind!
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A rough rule of thumb used to be that an electrical device is around 90% efficient - does that still hold with today's machines? So if you have one to generate the electricity, and one to use that electricity ( directly / indirectly from batteries), that gives you about 81% efficiency. It'd be interesting to see similar figures for mechanical and hydraulic transmissions.
 
td97

td97

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37201xoIM said:
I know 15X slushboxes are not great, but is that true? Diesel-electric is for units generally less efficient than direct mechanical drive (as on 172, 195 etc.) - but I would have guess about the same as diesel-hydraulic? But d-e does generally involve extra weight.

Am not an engineer, mind!
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Diesel-electric is highly efficient, more so than diesel-mechanical, as:
The diesel engine runs at its most efficient speed, continuously, unlike DMMU engines which cycle though (inefficient) speed ranges as per gearing/unit speed.
Electric motors are some of the most efficient mechanical devices around, likely upwards of 90% on a 319 (DC motor). Today's modern AC motors are likely >95%.
 
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37201xoIM

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Indeed, and thanks, both - was aware of said principles. The issues with D-E that lead it generally to be less favoured for low-power things like units and shunters have tended to be the increased weight and, to an extent, the 90% of 90% (i.e. transmission losses)... Obviously mechanical can't handle the power/torque in a proper loco, and hydraulic, while attractive on paper for saving weight, isn't necessarily more efficient - and is not always reliable in that sort of big application.
 
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edwin_m

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Grannyjoans said:
The problem with using the 769s on routes which don't see much electrified lines is fuel capacity. They really don't have much fuel capacity. I'm not sure what capacity the tanks are but I believe it is only around 400 litres, about half that of a 142 ?
Click to expand...

37201xoIM said:
Good grief, I did not know that! That is risible - and a potential killer. Was reading (here: https://www.railwaygazette.com/uk/welsh-fleet-deployment-programme-rationalised/55906.article?utm_source=RBUKnewsletter&utm_medium=email&utm_content=&utm_campaign=RBUKnewsletter- 05/03/2020) that in Wales they are apparently proposing to run them on the Rhymney line, almost entirely away from wires.


There's nowt difficult about wiring tunnels! Remember that a lot of OLE pioneers were in the Alps. And these days things like contact bars make it even easier. "Discontinuous electrification" has been largely debunked...
Click to expand...
At least on the Rhymney line they're never far from a depot and if necessary they could swap sets out for refueling between the peaks. The GWR Gatwick services have the opportunity to swap during the day at Reading. On the Southport run they're under the wires for a big slice of the time so fuel capacity shouldn't be an issue.
 
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geoffk

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edwin_m said:
On the Southport run they're under the wires for a big slice of the time so fuel capacity shouldn't be an issue.
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Will they changing traction at Bolton, or on the move at Lostock Junction? That would make a small difference. Until the recent changes both these services ran to Wigan NW of course, not to Southport.
 
Elecman

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If they extended the wires for another half mile on the Westhoughton Lines they could do the changeover on the fly clear of the Preston Lines in case a unit sits down.
 
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plugwash

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My understanding was that a mode switch on a 319/769 required shutting the train down. so would be done while stopped at a station.
 
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AndrewE

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plugwash said:
My understanding was that a mode switch on a 319/769 required shutting the train down. so would be done while stopped at a station.
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Well, isn't that just ideal for an intensively used network (not!) I suppose they are only for the provinces, so we can live with an extended station dwell, after all there haven't been any complaints of track capacity problems around Manchester have there?
So many stations have twin platforms for each direction that it will be easy for the next train to draw in and start its station business while the first is changed over ready to set off - I wish!
What a short-sighted short-cut.
 
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plugwash

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AIUI they switched in-station when on thameslink, and afaict that is a lot busier than Bolton.
 
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AMD

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The 769s are capable of changing mode on the move, however they will change at Bolton.
 
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geoffk

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AMD said:
The 769s are capable of changing mode on the move, however they will change at Bolton.
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...until the wires are extended to Wigan NW, then presumably at Hindley! Can trains be refuelled at Southport?
 
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Bovverboy

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Grannyjoans said:
The problem with using the 769s on routes which don't see much electrified lines is fuel capacity. They really don't have much fuel capacity. I'm not sure what capacity the tanks are but I believe it is only around 400 litres, about half that of a 142 ?
Click to expand...

a_c_skinner said:
How does that work out for range? (Googled it, what little there is says 500miles or comparable with 150s)
Click to expand...

A 769 doing Southport - Alderley Edge all day should do less than 200 miles on diesel. Even if it didn't touch the wires at all, it would still be less than 500.
 
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AM9

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Bovverboy said:
A 769 doing Southport - Alderley Edge all day should do less than 200 miles on diesel. Even if it didn't touch the wires at all, it would still be less than 500.
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Thanks for bringing this discussion back to reality. So for a journey of around 90 minutes with about 10 intermediate stops in 18 miles under diesel power and 5 stops in 24 miles under wires, a full day diagram uses about 40% or less* of a set of full tanks. Given that the design was based on the results of modelling the route from Manchester to Buxton ISTR, it would seem that the choice of ALD to SOP would seem to present little risk in the range dept. and is a good use of a bi-mode train. As far as the extra weight of the electric components (generator, traction electrics motors and a unused pantograph/transformer), it would seem that the higher efficiency of a DE transmission under most operational use would deliver a flexible bi-mode suited to the mixed nature of the route.
Of course, all of this kit needs a reasonable reliability in service, but as has been mentioned, it seems that Allerton's years of experience with the 319s has delivered improving MTINs recently, so the only additional significant items on the 769s are the generator/rectifier and the diesel engine, - both factory fresh hardware yet fully developed and proven elsewhere on other networks. Time will tell of course.
* The target for range was 500 miles diesel only. However, following tests, it was felt that 700-800 miles might be achievable which if delivered, might allow fuelling less than once per day's duties.
 
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CHAPS2034

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AM9 said:
Thanks for bringing this discussion back to reality. So for a journey of around 90 minutes with about 10 intermediate stops in 18 miles under diesel power and 5 stops in 24 miles under wires, a full day diagram uses about 40% or less* of a set of full tanks.
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Scheduled time between Southport and Alderley Edge is 110 minutes not 90

Distance on diesel Southport to Bolton is 27.11 miles according to RTT not 18

Intermediate stops between Southport and Bolton are 8 not 10
Meols Cop
Burscough Bridge
Parbold
Apperley Bridge
Gathurst
Wallgate
Hindley or Ince (or neither dependent on time of day)
Westhoughton

Intermediate stops under the wires after Bolton are 10 not 5
Salford Crescent
Deansgate
M'cr Oxford Rd
M'cr Piccadilly
Levenshulme
Heaton Chapel
Stockport
Cheadle Hulme
Handforth
Wilmslow

You did get the mileage from Bolton to Alderley right however. :D
 
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Grannyjoans

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Southport to Alderley Edge is quite a slow journey on current timings with an average speed of just 28mph. 110 minutes to do 52 miles.
 
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Killingworth

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At present the arrival in service of a few 769s will help the capacity issues, but if our present health scare carries on we won't have capacity issues!
 
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This thread is to discuss Porterbrook class 769 'Flex' trains for Northern.

If anyone wishes to discuss anything else, you are very welcome to create a new thread (in the appropriate forum section).

Any suggestions/ideas belong in the Speculative Ideas forum section please. I have therefore moved the suggestion regarding designating the Northern franchise as an R&D franchise into that area (along with the posts that replied to it).
 
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