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

Jamesrob637 · 3 Mar 2020

When you look at "Journey Check" of a morning and see "XX:XX Southport to Alderley Edge will be formed of 2 coaches instead of 4", you don't have to be Einstein to know that this is an out-and-back several times a day. Just putting 5 or 6 of these into traffic will by and large eliminate 2-car diesel working into and out of Manchester!

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plugwash · 3 Mar 2020

I'm sure I remember early on claims that extra seats were to be added to the 769s to reduce the maximum "crush-laden weight", did that happen in the end?

James James · 4 Mar 2020

a_c_skinner said:
I don't follow the anxieties about performance on electricity, they've done OK on Thameslink. The extra mass of the engines is about 10% which won't make a huge difference. In fact they will have 90% of the performance of the 319s. If my physics is right!

90.9% or 91% to be accurate. And that's only when not loaded with passengers.

a_c_skinner · 4 Mar 2020

Indeed, the effect of the mass of the engines is even less when comparing fully loaded vehicles!

Grannyjoans · 4 Mar 2020

A 769 has 90.9 or 91% of the performance of the 319 when running on electrified lines.
When running on diesel, what is it going to be then ? The Diesel engines only generate half the power that a 319 would normally get, so would they have only 45.5% of the performance of a 319 ?
It would be bad if that initial acceleration from 0 to 15mph is that much slower!

NoMorePacers · 4 Mar 2020

319s and 150s don’t have differentiated timings anyway.

a_c_skinner · 4 Mar 2020

Grannyjoans said:
It would be bad if that initial acceleration from 0 to 15mph is that much slower!

Ah, well that is more of an imponderable. However power isn't force and it is force that determines acceleration. We have to assume Brush knows more about this that we do. Mind you...
I suspect performance has been modelled pretty well, it was converting them that wasn't! I'd love to really know what the delay was between apparently trouble free running on the GCR and starting mileage accumulation on the main line.

JN114 · 4 Mar 2020

a_c_skinner said:
Ah, well that is more of an imponderable. However power isn't force and it is force that determines acceleration. We have to assume Brush knows more about this that we do. Mind you...
I suspect performance has been modelled pretty well, it was converting them that wasn't! I'd love to really know what the delay was between apparently trouble free running on the GCR and starting mileage accumulation on the main line.

Thought it had already been covered - redesign of the exhaust as it was out of gauge; while the physical fix was easy to install it invalidated emissions testing which had to be re-done; and that has a long lead time.

a_c_skinner · 4 Mar 2020

Ah, I'd forgotten that (sorry), though I was sceptical about it as the sole explanation because of how long it took. It would have been quicker to modify the platforms! With luck we are heading for sunny uplands where the conversion is quick and easy and not too costly and the minister has to make good on promises to sort out Northern.

superkev · 4 Mar 2020

Grannyjoans said:
A 769 has 90.9 or 91% of the performance of the 319 when running on electrified lines.
When running on diesel, what is it going to be then ? The Diesel engines only generate half the power that a 319 would normally get, so would they have only 45.5% of the performance of a 319 ?
It would be bad if that initial acceleration from 0 to 15mph is that much slower!

Yes the 4 319 motors have a continuous raiting totalling 1323bhp and will produce much more for a short time.
I can't see the 262hp per car 769 figuring very high in the Rail express magazine 0 to 60 times.
For interest the 319 is 0 to 60 in 70 seconds and the much
lighter 285hp per car class 156 is 124 seconds.
Perhaps the 769 should have been 3 car.
K

edwin_m · 4 Mar 2020

superkev said:
Yes the 4 319 motors have a continuous raiting totalling 1323bhp and will produce much more for a short time.
I can't see the 262hp per car 769 figuring very high in the Rail express magazine 0 to 60 times.
For interest the 319 is 0 to 60 in 70 seconds and the much
lighter 285hp per car class 156 is 124 seconds.
Perhaps the 769 should have been 3 car.
K

Traction motor power isn't relevant when running on diesel, as the diesel engines can't supply as much power as the motors could use. The electric transmission may mean the power is used more efficiently than on a Sprinter, which might help a bit at higher speeds.

I think we've had the discussion before that there are various critical bits of hardware on the unpowered centre car of the 319, which would have to be moved elsewhere if they were reduced to 3-car (unlike a 321). But with the power car already fully of electrics and the two end cars full of diesel stuff there probably isn't any room.

Greybeard33 · 4 Mar 2020

NoMorePacers said:
319s and 150s don’t have differentiated timings anyway.

Incorrect. There are separate timing loads for a Class 319 EMU and a Class 150/153/155/156 DMU. 319s are significantly quicker.

Mogster · 4 Mar 2020

superkev said:
Yes the 4 319 motors have a continuous raiting totalling 1323bhp and will produce much more for a short time.
I can't see the 262hp per car 769 figuring very high in the Rail express magazine 0 to 60 times.
For interest the 319 is 0 to 60 in 70 seconds and the much
lighter 285hp per car class 156 is 124 seconds.
Perhaps the 769 should have been 3 car.
K

2 minutes? The 156 has always seemed very ponderous. That confirms it.

NoMorePacers · 4 Mar 2020

Greybeard33 said:
Incorrect. There are separate timing loads for a Class 319 EMU and a Class 150/153/155/156 DMU. 319s are significantly quicker.

Not really. If you compare their timings on the Bolton corridor for example they are the exact same. Also worth saying how a DMU can easily substitute for a 319 and there’s no timing penalty.

Nymanic · 4 Mar 2020

NoMorePacers said:
Also worth saying how a DMU can easily substitute for a 319 and there’s no timing penalty.

Not universally true. Twice in 2019 I travelled on late-night Chat Moss stoppers pathed for a 319 but operated by single 156s. Loadings were light, but that didn't stop us losing nearly 10 minutes between Liverpool and Deansgate on both occasions. We got even later from there.

I also once saw a single 150 filling in on a Liverpool-Crewe run, that had lost 10 minutes by Earlestown.

Llama · 4 Mar 2020

Time lost won't just be dependent on power, but also on braking. The brakes on 319s are good, significantly better than the tread brakes on 150/156 units which might deputise.

Bovverboy · 4 Mar 2020

I once knew a truck driver who complained to his boss that the brakes on his truck weren't up to scratch. The response he got was: "Are you thinking of stopping?"

Greybeard33 · 4 Mar 2020

NoMorePacers said:
Not really. If you compare their timings on the Bolton corridor for example they are the exact same. Also worth saying how a DMU can easily substitute for a 319 and there’s no timing penalty.

Again, not true. If you subtract any pathing allowances, the Rochdale to Blackburn and Rochdale to Clitheroe services, pathed as a 150/3/5/6, are timed at 11 minutes non stop from Salford Crescent to Bolton. The Airport to Blackpool, Victoria to Preston and Alderley Edge to Southport services, all pathed as a 319*, are timed at 8.5 minutes between the same stops. That is 23% quicker.

*The Alderley Edge services are pathed as a 319 under the wires, presumably in anticipation of the use of 769s. The Hazel Grove services are pathed as a 323 and are also timed at 8.5 minutes.

Mogster · 4 Mar 2020

Nymanic said:
Not universally true. Twice in 2019 I travelled on late-night Chat Moss stoppers pathed for a 319 but operated by single 156s. Loadings were light, but that didn't stop us losing nearly 10 minutes between Liverpool and Deansgate on both occasions. We got even later from there.

I’ve travelled on them a lot in the past 30 years and 156s have always struck me as being very very slow. The data posted above suggests this was correct. Loading via the narrow end doors takes forever also.

Grannyjoans · 4 Mar 2020

142s, 150s and 156s are very very slow. There's hardly any difference between them speed wise.

Rob F · 4 Mar 2020

They were quicker than the first generation DMUs they replaced.

AM9 · 4 Mar 2020

Rob F said:
They were quicker than the first generation DMUs they replaced.

So what has that to do with a thread about converting MKIII EMUs to bi-modes?

warwickshire · 4 Mar 2020

Does anyone know pls when will the first 769 be expected to enter service on the southport to alderley edge route please.

JN114 · 4 Mar 2020

May TT change is the current plan AFAIK

warwickshire · 4 Mar 2020

Many thanks so it now appears the original 769 introduction has been put back from March and is now may tt.

Roger B · 5 Mar 2020

JN114 said:
May TT change is the current plan AFAIK

So not scheduled to be used until the Mat TT change, got that. But might they be introduced without fanfare prior to that, being swapped onto the occasional diagram - a so called 'soft' launch?

LNW-GW Joint · 5 Mar 2020

warwickshire said:
Many thanks so it now appears the original 769 introduction has been put back from March and is now may tt.

Introduction has been put back umpteen times in the last two years.
It looks more promising now, but don't take anything as certain.

a_c_skinner · 5 Mar 2020

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.

notlob.divad · 5 Mar 2020

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.

There is some truth in this. I was originally quite a big fan of this idea as it meant that there was an increase in cross compatability between Northerns EMU and DMU fleets, leading to commonality of spares, reduced driver training etc etc. If it had initially worked well, I could have seen good reasoning to convert more 319s and have them concentrated along with the 319s to create a uniform fleet. As yousay the 319s are now going, so the cross commonality is now goign with it and Northern are left with yet another microfleet.

Roger B said:
So not scheduled to be used until the Mat TT change, got that. But might they be introduced without fanfare prior to that, being swapped onto the occasional diagram - a so called 'soft' launch?

I would hope that as soon as they have sufficient numbers of drivers trained up to cover diagrams they will start introducing them.

a_c_skinner · 5 Mar 2020

But that is part of the problem of micro fleets. You train loads of people who will rarely drive them or take pot luck with the random driver allocator.

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

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