(my addition in orange bold
… they definitely ride more harshly than the trailers, same in the 321 …)
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Porterbrook Cl.769 'Flex' trains from 319s, initially for Northern
- Thread starter pemma
- Start date
(my addition in orange bold
… they definitely ride more harshly than the trailers, same in the 321 …)
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RailUK Forums
is it possible that they don't have different suspension settings (for economy reasons?), resulting in that harsher ride quality?(my addition in orange bold
ac6000cw
Established Member
The bogies on the motor car are a different design to the ones on the trailer cars (to accommodate the motors). Also the axle-hung/nose-suspended motors typical of that vintage of EMU will increase the unsprung mass of the powered axles compared to the the trailer axles, which may well give a harsher ride.
They have completely different bogies on the motor / transformer / pantograph coaches and hence completely different suspension on them
Thanks, that's what I hoped, it's just something we have to live with.
The gensets aren't exactly lightweight, not the 20 tonnes of a transformer and 4 traction motors but enough to warrant having a look at the suspension.
Well, a class 150 powered car weighs about 6 tons more than the 319 unpowered ones so maybe that is a guide.*
* yes I know that the 150 has a 213KW engine with a Voith transmission and mechanical drivetrain whereas the 769 will have a higher output of 390KW and a generator without a drivetrain. But the power to weight realtionship is not linear.
The 800 thread on here (and elsewhere) is a good record of issues and faults that have bugged the units. Remember the infamous IET launch day? Or the farce of 3 failed 800 sets blocking the GWML at Hayes and Harlington for several hours. Most recently they've had problems due to clogged air filters, IIRC. The GWR 387 introduction was much smoother by comparison, the main issue being a shortage of trained drivers due to the delayed completion of electrification to Didcot.
edwin_m
Veteran Member
The 150 runs on the same basic design of bogie as the trailer cars of a 319, as indeed do various other powered vehicles of which the 170 is probably the heaviest. So I don't think there's a major problem with the bogies carrying the weight of a genset.
The_Engineer
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I have just seen on LinkedIn (https://turbopowersystems.com/tps-auxiliary-power-supply-units-for-brush-traction/) that a company called Turbo Power systems has received an order for Auxiliary Converters for the Class 769 trains. These will replace the Motor-Alternator sets that supply three-phase AC and 110V dc for auxiliary loads. Replacing the MA set must be an expensive step, so I wonder if the instability rumoured operating on diesel (DC generator) supply is with the MA set?
Whattraintoday
Member
Would that include 220v plug sockets and USB charging points? (assuming the refurb includes those)
‘Cause that would be hilarious: “Ladies & Gentlemen, please don’t plug anything in, we’re going uphill”
I doubt that they will even bother with frippery like that anyway.
Greybeard33
Established Member
I see the TPS press release says that the contract is for the GWR fleet of 769s - not Northern or ATW. It also states:
Putting two and two together, maybe GWR has specified aircon, so more auxiliary power is needed than the existing MA set can provide? I have not seen any suggestion the Northern units will be retrofitted with aircon.
On the other hand, if Wabtec is not modifying the original 319 traction control package to limit current draw on diesel power, instead relying on current limiting in the generator controllers, the voltage on the traction bus could collapse if the driver is over-enthusiastic on taking power. The existing MA will be designed to tolerate only the (relatively modest) voltage fluctuations encountered on third rail or transformer-derived traction power.
Greybeard33
Established Member
Load sharing between paralleled DC generators is indeed a well-established technology. The current of each generator is measured and a bias fed back to each voltage regulator to null the difference. However, it can be tricky to implement. As with any feedback loop, there is a risk of dynamic instability, such that the load oscillates between the generators until one trips out. This is particularly likely if the load is non-linear, such as a 319 traction control package. And the problem becomes more complex if the generators are driven by dedicated prime movers, such as diesel engines, which have their own feedback loops to maintain constant generator speed.
I would be surprised if the 769 designers failed to anticipate the need for load sharing, but not surprised if it has proved difficult to implement successfully.
apk55
Member
MA sets are a relatively high maintenance item as they run continuously when the unit in service. They are also not very efficient. At the time these units were conceived power electronics was still developing and so the engineers designing these went for the tried and tested solution of an MA set (probably the same or very similar to those already used). Now with high voltage and fast semiconductor switches easily available designing an efficient static converter is comparatively simple. I would also expect some "off the shelf" designs being available for use in trams and trains, as most new designs use static converters and these could used or adapted.
You don't need to put anything together - the announcement of the GWR order in April said that their 769s would be fitted with air cooling equipment.
https://www.railwaygazette.com/news...o-lease-class-769-flex-trimode-trainsets.html
mushroomchow
Member
More guff info in this month's Railway Magazine, which to echo the complaints of the recent article in Rail Magazine sounds like it was right from the mouth of Porterbrook rather than an objective piece of journalism.
There was certainly no mention of the timescale information in last month's issue turning out to be false. Apparently, the first unit is now moving to the GCR for testing in August - pretty obvious when you think they need to get a unit there by later today to meet the July target - and they still expect fleet service on the Windermere line by December. We'll see...
Still no sight of a complete unit in the piece - the closest being a picture of the engine and the fitting of an exhaust pipe to the bodyshell. It's remarkable that we're still at the stage where journals and magazines are printing concept art of what they're supposed to look like with deadlines already missed and a revised target introduction date less than 5 months away.
I'm starting to fear that this farce could be a nail in the coffin of Brush Wabtec at a time that the complex as a whole is struggling.
There was certainly no mention of the timescale information in last month's issue turning out to be false. Apparently, the first unit is now moving to the GCR for testing in August - pretty obvious when you think they need to get a unit there by later today to meet the July target - and they still expect fleet service on the Windermere line by December. We'll see...
Still no sight of a complete unit in the piece - the closest being a picture of the engine and the fitting of an exhaust pipe to the bodyshell. It's remarkable that we're still at the stage where journals and magazines are printing concept art of what they're supposed to look like with deadlines already missed and a revised target introduction date less than 5 months away.
I'm starting to fear that this farce could be a nail in the coffin of Brush Wabtec at a time that the complex as a whole is struggling.
Northern have said the Manchester Airport to Windermere services will now be 195s from the outset, with it now going to be one of the first routes to get 195s. Alderley Edge to Wigan and Wigan to Stalybridge services could be switched to 769s tomorrow if they were available and crews were trained on them.
43096
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There’s more guff on web forums about it than it magazine articles.
The magazines are only going to get restricted access to the details of the project - they can only go on what Porterbrook and Wabtec tell them. What else do you propose they do, bearing in mind they need to maintain relationships with the companies involved?
How much more time and how much more money needs to pass before the project is deemed unviable? It seems to have been going on for quite some time. I understand that there will be extra time and expense in the building of the first unit, but surely that’s going to be translated into full production? What would the cutoff points be?
Porterbrook are a commercial company. They'll be a limit to how much money they can get from the government either directly or indirectly but no limit to how much of their own money they put towards it. Perhaps getting the agreement for 19 x 769s for GWR has meant they are willing to put more of their own money in?
Rail Blues
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Interesting how you set yourself up as apologist in chief for Porterbrook and Wabtec. All your posts seem to consist of 'move along, nothing to see here' and rubbish sh any post that suggests what is patently obvious - this project is turning into a total dog's breakfast.
I would suggest that rail journalists act like journalists, if I want to read pr guff from Roscos I'll get it straight from the horse's mouth, I don't expect to pay the thick end of a fiver for the privilege.
43096
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Ah, I see. Anyone who posts something contrary to your view is an apologist for the organisations involved. The reality is probably somewhere between the PR view (always going to accentuate the positive) and the “we’re all doomed” view prevalent on here.
While clearly the Project is late, although for Northern at least its probably less of an issue now with the current Timetable shambles, unless you work for Wabtec or Porterbrook you are unlikely to have any real idea how this project is progressing, or much evidence for the comment that its total dogs Breakfast.
Personally I don't agree with the project, its spending a lot of money on a 30 year train, but at the end of the Day they have been ordered 3 TOC's and as far as is in the public domain at present that's what Porterbrook and Wabtec intend to deliver.
I would guess another year or so. The project is only a disaster rather than a failure if they don't get enough units into service for the December 2019 timetable change. Northern can delay pacer withdrawals until then but after that it would be 8 units / 32 coaches short. W&B will be very stretched but can just about cope until December 2019 without them. Of course the penalty dates in the contracts between Wabtec, Porterbrook and the ToCs maybe different. My guess is that Northern will quickly catch up with its 142 withdrawal schedule as long as the 195s start to arrive and cascaded units are not delayed much more than currently. The (Porterbook owned) 144s could easily all stay until the last day possible to cover for the 769s.
Will they be even needed for Northern? Will Northern's fully expanded timetable be even fully implemented anytime soon?
And also the 769s could operate the Manchester Airport to Blackpool North services? Quite a few of these are cancelled everyday due to a lack of trained drivers on the 156/158s.
Of course, we wouldn't even be talking about this if this route was electrified on time and the 769s were in service as scheduled!
This route is operated using 319s.
absolutelymilk
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Presumably js1000 meant the services from Manchester Piccadilly via Bolton.
Diesels under the wires counts as a form of chaos?!