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

[DustyBin]

That is perhaps a better idea if you want to prevent drivers accidentally switching to AC mode, but does nothing to reduce dead weight.

Dead weight isn’t the issue as @Greybeard33 and @AM9 have explained. Even in Class 319 guise these units were/are particularly prone to loosing traction in slippery conditions (in my experience as a passenger) so the last thing they need is less weight in the motor coach with the additional weight of the engines elsewhere.

Whilst there may be an inherent performance issue with these units in diesel mode (or not, I honestly don’t know), in electric mode(s) they were nothing like as sluggish on Thameslink. They weren’t noticeably slower than say a 317 or 321, which whilst not exactly rocket ships by modern standards aren’t considered particularly lethargic either.

 

[AM9]

They have a pantograph well, and Siemens include the letter “P” on the relevant carriage designation on its data plate.

I believe that some time around 2000, the DfT mandated that all new EMUs were to have a pantograph well even if they were 3rd rail only. Remember that it is more than a cosmetic 3 metres of flat roof, - the body needs different stiffening to retain it's crashworthyness so it must be there from manufacture. The bogie suspension would be set up to carry (or not) the transformer weight, maintaining the designed ride dynamics. Back on topic, I believe that the 769 DTSOs didn't have suspension mods to carry the gensets, which might account for the speed restriction even though it was reported that during design testing, they achieved 90+ mph in diesel mode. When I rode 769424 last year between Wallgate and Southport, the ride in the DTSO was smooth and quiet so the suspension under that car was probably carrying a load equivalent to a full passenger load, i.e. 7 tonnes.

 

[TurboMan]

But have they run at that speed there, or anywhere else since they had Diesel engines fitted?

Yes, on AC between Reading & Didcot, and on DC between Redhill & Gatwick.

 

[507020]

Yes, on AC between Reading & Didcot, and on DC between Redhill & Gatwick.

So the 75mph limit is a local instruction between Salford Crescent and Bolton.

 

[jfollows]

So the 75mph limit is a local instruction between Salford Crescent and Bolton.

I think the speed limit is 75mph between Salford Crescent and Bolton, with differential higher speed limits for "MU" trains of 90mph and 100mph, however I guess the 769 isn't part of the "MU" category. Happy to be corrected!

EDIT Looks like the speed limit increases to 80 from 75 down through Farnworth.

 

[AM9]

The 769s may have been considered a bit front heavy for Network Rail so may have put a 75mph speed limit on them. Of course, the track doesn't see anything different when the mode is changed so that would also apply on the stretches where they would nomally be expected to run in electric (ac/OLE) mode.

 

[jfollows]

I found a report "Differential Permissible Speed Categories MU, DMU, EMU, HST & SP Technical Report
T1163" which said

However, there were groups of EMU vehicles which produced a higher vertical and lateral force than other DMU and EMU vehicles with a similar axle load. These included classes 31x (and the converted Class 769), 32x and 442 which have a reported higher unsprung mass.

 

[AM9]

I found a report "Differential Permissible Speed Categories MU, DMU, EMU, HST & SP Technical Report
T1163" which said

In oher words, MKIII bogies carrying heavy EE507/Equivalents * tend to be heavy on the track.
Yes I know the 442s had even heavier 546s.

 

[Tynwald]

Class 769 banned from running on AC I hear.

 

[skyhigh]

Class 769 banned from running on AC I hear.

Keep up at the back

From this thread on Monday:

769 movements are now to run in diesel mode throughout and must not be used in AC mode until further notice apparently.

 

[507020]

I found a report "Differential Permissible Speed Categories MU, DMU, EMU, HST & SP Technical Report T1163" which said however, there were groups of EMU vehicles which produced a higher vertical and lateral force than other DMU and EMU vehicles with a similar axle load. These included classes 31x (and the converted Class 769), 32x and 442 which have a reported higher unsprung mass.

This would mean all classes 310-325 including aluminium bodied 313-315s and 323s have as high of as an unsprung mass as Mk1 and Mk3 units, which I highly doubt to be the case.

 

[AM9]

This would mean all classes 310-325 including aluminium bodied 313-315s and 323s have as high of as an unsprung mass as Mk1 and Mk3 units, which I highly doubt to be the case.

Not sure about the PEP derivatives, they have smaller output GEC motors (110hp) so they should have a lower unsprung weight even when nose hung.

 

[Bikeman78]

Dead weight isn’t the issue as @Greybeard33 and @AM9 have explained. Even in Class 319 guise these units were/are particularly prone to loosing traction in slippery conditions (in my experience as a passenger) so the last thing they need is less weight in the motor coach with the additional weight of the engines elsewhere.

Whilst there may be an inherent performance issue with these units in diesel mode (or not, I honestly don’t know), in electric mode(s) they were nothing like as sluggish on Thameslink. They weren’t noticeably slower than say a 317 or 321, which whilst not exactly rocket ships by modern standards aren’t considered particularly lethargic either.

I'd like to put a 317 and a 769 on diesel next to each other heading north out of Tottenham Hale. I reckon the 317 would pull ahead very quickly, getting to 85 mph in around 2.5 minutes. Would a 769 ever get to 85 on the flat? I have no idea what Northern have done to the 769s if they are no better on electric than diesel.

 

[Geeves]

It was soon found that 30s years of 319s being hammered on Thameslink translated into dead 319s up north, more delicate driving styles were told to be applied.

As for 796s at Northern, I'm not sure the TOC can be blamed for their performance and what are the comparisons to be made? No one else has ran them in passenger service using both modes so far. GWR are seemingly on permanent test mode. I've had a fair few rides on 769s now. They aren't bad once they get going, nice smooth acceleration anyway both on and off the wires.

 

[Bikeman78]

It was soon found that 30s years of 319s being hammered on Thameslink translated into dead 319s up north, more delicate driving styles were told to be applied.

As for 796s at Northern, I'm not sure the TOC can be blamed for their performance and what are the comparisons to be made? No one else has ran them in passenger service using both modes so far. GWR are seemingly on permanent test mode. I've had a fair few rides on 769s now. They aren't bad once they get going, nice smooth acceleration anyway both on and off the wires.

The 317s have been hammered (especially the GN 12) and indeed they still are. They wouldn't keep time on the Hertfords if they pootled along. Better motors perhaps?

 

[DustyBin]

I'd like to put a 317 and a 769 on diesel next to each other heading north out of Tottenham Hale. I reckon the 317 would pull ahead very quickly, getting to 85 mph in around 2.5 minutes. Would a 769 ever get to 85 on the flat? I have no idea what Northern have done to the 769s if they are no better on electric than diesel.

I’m pretty certain it’s the driving style at Northern that holds them back, certainly in AC mode anyway. They seem to pull away very(!) gently and then open up once at 20-25mph.

 

[D9006]

Realtime Trains | 2W07 0930 Stalybridge to Southport | 30/05/2022

Real-time train running information for 2W07 0930 departure from Stalybridge to Southport on 30/05/2022. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

intresting as was on time,

the inbound was worked by 424 arrived 8 late

 

[175001]

It was cancelled at Wigan, to be sent to Springs Branch for refueling.

1116 SOP - ALD diverted to Victoria and sent to NH for refueling.

 

[507020]

It was cancelled at Wigan, to be sent to Springs Branch for refueling.

1116 SOP - ALD diverted to Victoria and sent to NH for refueling.

When will they be allowed to run on electric mode again?

 

[D9006]

Had 456 on Saturday afternoon, made a spirted climb to Bolton , running at 73-75 up the hill, pulled away from Salford crescent as good as if on the juice

 

[175001]

When will they be allowed to run on electric mode again?

Once the cause of the fault is found.

 

[Pete_uk]

Once the cause of the fault is found.

And fixed, hopefully!

 

[507020]

A 769 service towards Southport (presumably the intended 21:33 arrival 2W22) completely failed today, with attempts to restart ultimately being unsuccessful and passengers eventually evacuated in the presence of emergency service after being stuck for several hours. I have seen video footage (not public unfortunately) of passengers on a 769 in the dark.

 

[LowLevel]

A 769 service towards Southport (presumably the intended 21:33 arrival 2W22) completely failed today, with attempts to restart ultimately being unsuccessful and passengers eventually evacuated in the presence of emergency service after being stuck for several hours. I have seen video footage (not public unfortunately) of passengers on a 769 in the dark.

Ran out of fuel apparently, then the rescue unit had issues when they tried to couple. Eventually took the passengers away on the rescue unit and then sent it back to pick up the other one.

 

[AM9]

Ran out of fuel apparently, then the rescue unit had issues when they tried to couple. Eventually took the passengers away on the rescue unit and then sent it back to pick up the other one.

So effectively, recovery from a fuelling error frustrated by a dodgy coupling. Could have happened to any 30+ year-old DMU.

 

[craigybagel]

So effectively, recovery from a fuelling error frustrated by a dodgy coupling. Could have happened to any 30+ year-old DMU.

But would the fueling error have occurred if the unit was able to run on electricity on part of its journey as it's designed to do but is currently forbidden?

 

[AM9]

But would the fueling error have occurred if the unit was able to run on electricity on part of its journey as it's designed to do but is currently forbidden?

If whoever's responsibility it is to ensure the fuel levels are as stipulated makes such a mistake, then there must be a plethora of other 'errors' likely to befall services. Running on diesel under the wires was planned, documented and signed for, so normalised in that context.

 

[507020]

Ran out of fuel apparently, then the rescue unit had issues when they tried to couple. Eventually took the passengers away on the rescue unit and then sent it back to pick up the other one.

I must add that I was mistaken about the timing and it was the earlier service 2W20, but where were the passengers taken by the rescue unit if the line was blocked by the failed one? Was it back to Burscough Bridge or on to Southport. Either one would have required an amount of wrong direction running. The failed unit must have been taken back to Wigan.

So effectively, recovery from a fuelling error frustrated by a dodgy coupling. Could have happened to any 30+ year-old DMU.

In theory yes, but both such issues are much less likely to affect Sprinters which have larger fuel tanks and are split and joined more routinely.

But would the fueling error have occurred if the unit was able to run on electricity on part of its journey as it's designed to do but is currently forbidden?

The fuelling error was that someone at the depot forgot to put fuel in it or didn’t put enough fuel in it, or that it didn’t make it as far as the depot when it was due to be refuelled. It may have just used slightly more fuel than had been accounted for given that it had almost enough left to reach Southport, from where it would have to have been dragged back.

Running on AC from Bolton as intended would of course have conserved the limited fuel available following the fuelling error and prevented passengers from being stranded.

 

[Wyrleybart]

As a matter of interest, can 769s received fuel at Wigan ? I may be wrong here but I get the impression some of the 769 diagrams are based in Wigan, rather than Allerton or Manchester where the units would probably be topped up every time they went onto a diesel depot. Apologies if I am wrong in my assumption.

 

[AM9]

In theory yes, but both such issues are much less likely to affect Sprinters which have larger fuel tanks and are split and joined more routinely.

No, whatever the range per load, if somebody forgets to fill a tank, the train will grind to a halt. Sprinters are joined and split because they frequently are required to carry more passengers than a single unit can accommodate, - it is not a failure that 769s do have sufficient room

The fuelling error was that someone at the depot forgot to put fuel in it or didn’t put enough fuel in it, or that it didn’t make it as far as the depot when it was due to be refuelled. It may have just used slightly more fuel than had been accounted for given that it had almost enough left to reach Southport, from where it would have to have been dragged back.

Whichever was the cause, it was a failure of the planning, process or implementation.

Running on AC from Bolton as intended would of course have conserved the limited fuel available following the fuelling error and prevented passengers from being stranded.

No, if that was the case, the fuelling regime would have longer intervals between fillings, but still vulnerable to poor housekeeping.