Given just how intensively all Thameslink rolling stock was/is/will be worked, any comparison of their reliability with much more leisurely deployments of equipment on lines radiating from provincial cities is pointless. Their loading and speed/stopping patterns are more arduous than any other MKIII MU types and over 30 years their service has been - all things taken into consideration - relatively reliable.
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Porterbrook Cl.769 'Flex' trains from 319s, initially for Northern
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Greybeard33
Established Member
Northern's 769s will be based at Allerton with the 319s and operate over similar routes. So I would expect that the current reliability of the Northern 319s is more relevant to the Northern 769s than the historic reliability of the Thameslink fleet.
Whether that will read across to TfW and GWR remains to be seen.
158820
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Are the 2 769s still at Allerton? Tony Miles was reporting they had faults and Northern wanted them gone off their depot.
thealexweb
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There have been photographs posted in the last week that showed them both still there.
As I don't know what the 319s' reliability is faring on the NW electric lines, I'm not quite sure how to interpret your comment. I know that they were troublesome when they were first introduced, but much of the trouble was put down to the maintainers hitting a learning curve with their 'quirks'. It seems that their reliability has improved sufficiently for them not to get regular criticism, so I assume that the support teams have now got the gist of them.
So, back to the prognosis of their future performance, especially as class769s, - on diagrams with both electric and diesel mileage, (say 50% each), I would imagine that the electrics would get an easier time away from OLE than under it. That would be because the diesel genset is limited to a maximum power well below the continuous rating of the traction motors, and of course the transformer/rectifier/pantograph would be unused for that time. When powered by diesel, the engine and generator would be much newer than the rest of the equipment so their reliability should be no worse than that on a new train.
As far as the additional weight of the genset is concerned, this has been discussed more than once in this thread in that their combined weight (i.e. two per 4-car set) is similar to a full passenger load, which the units were no stranger to over much of their 30 years in Thameslink use. Furthermore, those loads were regularly carried for 30-50 miles, which is the equivalent of trains full loaded including standing passengers, all the way from Lime St and Piccadilly, - something that I don't believe happens except maybe in times of severe disruption.
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Charlie Smythe
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I don't think the extra 15 tonnes added to the unit (which brings the total weight from 140 to 155 tonnes) will be an issue, but it certainly wont help.
palmersears
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Still there. They've moved around slightly in the last 10 days, and are now sat together on the third or fourth road in from the mainline.
158820
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Thank you.
anthony263
Established Member
Think tfw are having another 769 delivered this week according to the rumour mill
PHILIPE
Veteran Member
My point was that the additional weight should have a negligible impact on reliability when running on electric compared with a class319, (given their years of much heavier useage than on Thameslink roles, than they are likely to see in the provinces. Also, the additional weight under diesel will stress the original motors (and DC-DC electronics) far less than when they are powered from OLE/3rd rail as the maximum power available from the diesel genset is considerably lower. Therefore the traction system is unlikely to be overstressed, especially the older items.
Charlie Smythe
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I obviously misunderstood your other comment. I agree that under electric the additional stress will be negligible. Although unit performance on diesel will be interesting seeing as there is only 1050hp for 155 tonnes.
Greybeard33
Established Member
Do you have any evidence that the dire reliability/availability of Northern 319s is caused by "overstressing" the traction system? In any case, Northern 769s will be powered from the OLE for substantial portions of their diagrams, with similar stresses to their 319 cousins.
a_c_skinner
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All this is rather academic until these units manage to get out onto the main line for testing. For me it remains difficult to add all this up. The units have worked on GCR metals, but I've not seen reports of how much. Deliveries are going on. Those things add up to a project going well, but there is no sign of testing on the big railway, despite Northern having had finished unit(s) for a good while.
At risk of sounding silly, why do they need to test anywhere other than where they already have? There won't be gauging issues, by definition, and traction training for train crew can happen pretty much anywhere I would have thought (and should be pretty minimal anyway). For me, it would be unsurprising to see them enter service with zero to minimal testing on NR infrastructure.
a_c_skinner
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We can only hope you are both right, but I had imagined they need to accumulate a lot of mileage at speeds faster than on the GCR (even at its testing speeds) on diesel. Testing isn't (I think) in the hands of the final operators but one of the new freight companies whom I assume were prepared for it. Even if the putative testers are not ready surely someone else would have been brought it?
Killingworth
Established Member
If I were trying to introduce fleets of brand new trains, and redeploying fleets of older trains, I'd want my crews to be fully up to date with them and their routes before looking at 2 newly delivered units.
It's a question of priorities. However, it must be a concern as to whether Northern may be having second thoughts about 319s and that must knock on to 769s. If they are to be introduced in the near future surely there need to be more than 2 available very soon? Where are we at with further units?
It's a question of priorities. However, it must be a concern as to whether Northern may be having second thoughts about 319s and that must knock on to 769s. If they are to be introduced in the near future surely there need to be more than 2 available very soon? Where are we at with further units?
They’ll need to do route proving - that is checking platform stepping distances and the like. That tends to be done by the operator themselves.
Beyond that, maybe some acceptance mileage accumulation; but before they can do that there needs to be staff competent to fix the units if they fail out in the field. As I understand it that’s what the units were at Allerton for - fitter training.
But I predominately agree with Matthew S; the amount of “testing” required seems greatly over-egged.
Beyond that, maybe some acceptance mileage accumulation; but before they can do that there needs to be staff competent to fix the units if they fail out in the field. As I understand it that’s what the units were at Allerton for - fitter training.
But I predominately agree with Matthew S; the amount of “testing” required seems greatly over-egged.
a_c_skinner
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That would be good news if it is correct, but will units with a completely new traction system, retrofitted in a way never done before, go out without a good deal of mileage accumulation on the main line? The longer we wait the less plausible it is that the units are capable of working well as delivered. But units are being delivered so who knows?
It’s not a new traction system though. It’s just a pair of diesel generators to power the existing traction system. Once they’ve verified that that doesn’t change the interference output of the train (the purpose of running on the GCR). Then it’s just a 319 with a diesel generator. 319s are a known quantity. They don’t need miles and miles of testing.
You answer your own point in your last sentence. Deliveries to other operators are continuing; with no change to (admittedly revised) delivery schedules. If there was some serious issue uncovered the production line would have stopped; deliveries wouldn’t be happening. But units are still being dragged to Loughborough for conversion. TfW are due to get another unit this(?) week.
All this points to there being nothing wrong with the units themselves; and the delays being wholly down to the operator concerned not getting its act together to do the bits it needs to do to introduce these trains into service.
You answer your own point in your last sentence. Deliveries to other operators are continuing; with no change to (admittedly revised) delivery schedules. If there was some serious issue uncovered the production line would have stopped; deliveries wouldn’t be happening. But units are still being dragged to Loughborough for conversion. TfW are due to get another unit this(?) week.
All this points to there being nothing wrong with the units themselves; and the delays being wholly down to the operator concerned not getting its act together to do the bits it needs to do to introduce these trains into service.
You've oversimplified things a bit I think. There's been some electrical changes as well particularly with the multi working system (whether it's planned to be used or not) now having to cope with driving what is effectively a completely different set up. I don't know any particular details but it's more than just slinging a generator underneath.
LNW-GW Joint
Veteran Member
Northern don't have a lot of choice.
It very much is a DfT priority programme (as a replacement for axed electrification schemes), and it impacts on the ability to remove Pacers by year-end.
There's also not a lot happening on the CAF front to distract Northern.
It is indeed baffling that the 769s have not emerged on the main line yet.
a_c_skinner
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The thing that is intriguing me is the dissonance between these badly needed units having not ventured on to the big railway after a considerable pause and the project (as a lot of people have said) seemingly going perfectly well from every other point of view (building, ordering, delivering and not a word from the makers about any problem). The pause is now at a length that makes explanations like fitter training or concentrating on other units being introduced increasingly difficult to sustain.
Last news I had on the units several weeks ago was that there was an issue with the air suspension and therefore the braking affecting the driving vehicles. The brake pressures in each brake step are determined by the air suspension system.
TfW have been getting on with fitter training on Canton; and as I said are due to take delivery of a second unit soon. GWR have been continuing a lot of their behind the scenes preparations for getting their units delivered in the summer, so they can be introduced as quickly as possible.
The 769 introduction with Northern is now entirely within Northerns court. If they’re not training the staff - as is allegedly the case - then that perfectly explains the delay. Why that’s the case, or why it’s taking so long is another question.
Kind of. The greater weight on the air suspension will cause the brakes to apply more firmly; but that’s what’s wanted as the vehicles are heavier, it needs more brake force to decelerate at the same rate.
Perhaps the small amount of low speed movement they’ve done on Allerton has shown up something they don’t like. But the system can be tuned, it’s an easy job but it needs verification once it has been done. That means venturing out on the mainline which needs staff trained to do it.
No, and as I've said upthread, I don't have any knowledge of their current reliability performance other than assuming an improvement from the lack of complaints here, as were prevalent when they were first introduced, - hence my comment about maintainers getting used to them.
However, in post #3354, you commented: "Am I right in thinking that the conversion package does not include any reliability improvement mods?", so addressing the impact of the conversion on critical components of the units traction system, i.e. the effect of the additional 7'ish tonnes of genset/fuel tanks added to the DTSOs, I surmised the relatively small additional load under ac conditions (likened to a full passenger load in 2 of the 4 cars) and the lower loading on the motors when under diesel power that was unable to provide more than about 60% of the motors' continuous ratings, (which is in effect a derating of the DC electric traction components when running under diesel). In reliability engineering terms those changes with a new modern diesel engine I contend would be somewhere between reliability neutral and slightly improved. The other issue briefly discussed upthread was that of adhesion, for which I posted figures showing the minimal reduction of percentage adhesive weight for empty, full and crush loading for class769 stock compared with class the original class319s.
As I understand it, the theoretical maximum weight of the vehicles has exceeded the capabilities of the braking system and the units need modification before being permitted to run. Modifying the braking and air suspension system might not be enough in itself - the greater demand for air for braking (and to a lesser extent suspension) depletes the main reservoirs quicker. If one of the two main air reservoirs were isolated on the unit (perfectly plausible situation) then demand could exceed supply very quickly. The units have to be fit to run under degraded as well as normal operation.
That’s a fundamental design defect and would mean that the various parties involved have gotten their sums badly wrong. If the flaw were that serious; then production and delivery would have been stopped. It hasn’t.
A bit of retuning the braking system due to the additional weight sounds perfectly plausible; although surprising that it wasn’t uncovered in the 75mph running on the GCR.
If this is true about the brake system as the weight of the additional generators was a known quantity is it not odd that it’s only been flagged as a show stopper now?
No news from the DfT about the Castlefield corridor improvement works, no 195s, no 769s, broken 319s... As a daily Northern West of Manchester commuter I’m looking forward to the next few months greatly...
No news from the DfT about the Castlefield corridor improvement works, no 195s, no 769s, broken 319s... As a daily Northern West of Manchester commuter I’m looking forward to the next few months greatly...