Class 170101
Established Member
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One would hoper that the technology has moved on and potentially got smaller for a given space such that everything fits whilst doing a similar job to a Class 150.
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Porterbrook Cl.769 'Flex' trains from 319s, initially for Northern
- Thread starter pemma
- Start date
One would hoper that the technology has moved on and potentially got smaller for a given space such that everything fits whilst doing a similar job to a Class 150.
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edwin_m
Veteran Member
One would hope, but given the problems with the 230 and the number of delays to the 769 project (not all fully explained despite recent posts on here), I personally remain to be convinced that the engineering is sound.
The engine and the altenator chosen are both said to be proven under mainland Europe rolling stock, however there is always the issue of the actual layout within the probably (slightly) smaller space under class 319s. It is noted that the climate here has a smaller min to max temperature range than most of the continent, particularly in summer conditions.
They’re undergoing testing right now, which at face value seems to be going rather successfully? Northern have now said an actual date they’re working towards, which seems eminently achievable. Why the melodrama?
There are some posters on this thread who seem to want it to fail. If it does, (I hope not), just wait for the chorus of "I told you so!"
edwin_m
Veteran Member
If you're including me in that then I certainly don't want it to fail, but my gut and 30+ years in railway engineering suggests that if it has taken this long to get into service, they may have had to accept some less than ideal solutions that could cause problems later. Class 50 and Class 180 are examples of trains that never fulfilled their initial promise due to poor reliability.
No, you weren't on my mind when I wrote that. I don't know how long it might be before the true story about the delays gets out, but Greybeard's calm assessment of the events that are known outside the project in his post #4045, suggests that delays caused by the out of gauge exhaust system, it's subsequent revision of the design followed by the need to repeat some testing may have been hampered by material delays and access to test facilities. If the rail industry has queues for test houses anything like the avionics industry, then I am not surprised. Trying to explain that sort of problem to a lay press and the travelling passengers would probably be unproductive and an unnessary distraction from the task in hand.
The bottom line is that the 769 has been adopted as a short term (e.g. 10 year) solution to the lack of DMUs, and has a promise of an easily deployable bridge for when electrification resumes. I doubt that any more diesel mechanical units will be bought (after the 195s currently committed) and as DEMUs have been used continuously since the 1950s, their flexibility and convertability could well be a pointer to future acquisitions to meet aspirations of decarbonising the railway..
edwin_m
Veteran Member
Taking a more optimistic view for a change, if Porterbrook have been able to develop a reliable yet compact genset powerful enough that two of them can power a 4-car suburban unit. A DEMU with a similar configuration would have underfloor space on the other two cars, potentially allowing it to be built or converted later as a bi-mode.
As I said ~6 months ago on this thread - Engine testing is/has been major pinch point for the last 2 years with the new on road drive cycle meaning every current product needs testing (not just new designs) and Stage V for NRMM in 13 months time so getting test cell access is difficult.
[Testing has to include the full exhaust system these days.]
I have commented the same several times in the 195 thread, (e.g. #147) about the need for such developments. There really is an opportunity to develop designs of 'convertible' multiple units with motored bogies and a common equipment space, - probably as an underfloor sled that can fit between the bogies on both a 20m and 23m body. Such a sled should accommodate a diesel/alternator, a transformer/rectifier*, or a battery pack (in various capacities).
*At least one car would have a pantograph well and provision for HV feeds to the space where a transformer/rectifier would be fitted.
Probably so do most of us, but Grayling killed the last opportunities and I can't see any rush to give plenty of sound schemes being proposed much of a chance of happening.
Greybeard33
Established Member
Which correlates with this post:
It appears that at least two of these units are going to Long Marston for storage, not to Loughborough for 769 conversion:
331s have taken over some 319 diagrams this week.
TrainTrackJack
Member
does anyone know when testing begins for 110MPH running on the WCML?
What 110mph testing?
In a thread about class 769s, what would they be testing at 110mph? Even a pristine 319 can't reach that sort of speed!
samuelmorris
Established Member
The 10% over maximum rated speed for testing rule I assume?
samuelmorris
Established Member
It may not be a hard and fast rule, but certain fleets have been subjected to it.
themiller
Member
It depends upon what's in the specification/contract.
Drivers on here say that the 319s never quite reached 100 in service so maybe it wasn't necessary back in the '80s, except to prove that they could stop if they saw a red on the way down from Elstree Tunnel.
samuelmorris
Established Member
I'm pretty sure 321s which were very similar, were tested up to something quite extraordinary like 117mph.Drivers on here say that the 319s never quite reached 100 in service so maybe it wasn't necessary back in the '80s, except to prove that they could stop if they saw a red on the way down from Elstree Tunnel.
Surely a big part of the 230 & 769 projects is that they're not new trains so you don't have to do all the testing again? I'd have thought running overspeed would be in the 'don't need to do that' column.
edwin_m
Veteran Member
To get exemption from re-running a test you'd need to convince people that you haven't made the factors that affect the test result any worse. Since the train is now heavier its braking performance can't be relied on to be the same so I would think the brakes would need testing again and indeed such tests were reported on here a few weeks ago. Part of that is likely to be braking from an overspeed.
Sleeperwaking
Member
- Joined
- 20 Oct 2018
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- 166
For a new-build fleet complying with EN14363 (Testing and simulation for acceptance of running characteristics of railway vehicles - running behaviour and stationary tests), there's a European Railway Agency document (ERA/TD/2012-17/INT) that permits a dispensation from repeating tests if the new fleet's parameters fall within specified amounts of a previously tested / compliant fleet's parameters, e.g. if the primary sprung mass is within +/- 5%.
Which is a long winded way of saying that if the changes are relatively minor, then they may not have required 10% overspeed tests. TBH, overspeed tests can be a right pain to organise, so there would have been an incentive to avoid them if at all possible.
Which is a long winded way of saying that if the changes are relatively minor, then they may not have required 10% overspeed tests. TBH, overspeed tests can be a right pain to organise, so there would have been an incentive to avoid them if at all possible.
Tracked
Established Member
Might be late to the party (holiday and weather, so I've not been using Doncaster station for a week or so), but I noticed the 769's have now gone from the Wabtec siding over from Platform 8 @ Doncaster, first time they've not been there for ages. Replaced by the knackered 47 from the backyard, I have a feeling someone's going to tell me they've only swapped places 