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

[WatcherZero]

Mention in WalesToday talking about welsh franchise that they've completed testing at 75mph and are now moving on to testing them at 85mph.

Yeah RailEngineer says the designers models show they are theoretically capable of 87mph on the flat under diesel power while retaining 100mph under wires. Acceleration wise they are supposed to beat out a 150 at low speed but lose slightly to them at higher speeds.

 

[edwin_m]

Yeah RailEngineer says the designers models show they are theoretically capable of 87mph on the flat under diesel power while retaining 100mph under wires. Acceleration wise they are supposed to beat out a 150 at low speed but lose slightly to them at higher speeds.

It quotes "balancing speed" which is the speed at which the output from the engines exactly matches the various losses and resistances. Hence it will take literally forever to reach balancing speed unless assisted by a following wind or a falling gradient. I would expect the balancing speed to be lower on the GWR versions as they will have air conditioning which adds to the engine load - unless the engines are also uprated.

I'm rather surprised by the second part of the statement as I'd expect the 769 low-speed acceleration to be lower with less of the weight on powered wheels than a pair of 150s. Near the top end of the speed range the electric transmission should allow the engines to run at optimum speed for the power required, rather than being locked mechancially to train speed, which might result in better performance.

 

[driver_m]

Forgive me here, but wont they be expected to be tested at 110mph?! Now before you snort your derision towards me, you all know a train has to be capable of being safe at speeds over the allowed limit. Therefore if the train as a 319 is allowed at 100mph. Doesn't that theoretically mean that it should be tested at 10% over? Yes I know full well the only way it would ever do 110 is to drop it from the outer atmosphere, but would this mean it will be limited to 75 on both modes until it can be proven?

 

[hwl]

I'm rather surprised by the second part of the statement as I'd expect the 769 low-speed acceleration to be lower with less of the weight on powered wheels than a pair of 150s. Near the top end of the speed range the electric transmission should allow the engines to run at optimum speed for the power required, rather than being locked mechancially to train speed, which might result in better performance.

EMU acceleration time to 50mph is typically half that of hydraulic / mechanical transmission DMUs as they can supply far more power at the wheel at low speeds, hence I'm not surprised by that comment.

 

[59CosG95]

FWIW, I'm speculating that the GWR units will be used on the Reading-Newbury, Reading-Basingstoke, and North Downs services; while the North Downs is fairly self explanatory, their lower top speed may give them an advantage on the B&H (as 387s will no doubt be prioritised for the Paddington-Reading-Didcot corridor), and they can then be used to send all the 165s/166s west (though that may have been already implied).

 

[JN114]

FWIW, I'm speculating that the GWR units will be used on the Reading-Newbury, Reading-Basingstoke, and North Downs services; while the North Downs is fairly self explanatory, their lower top speed may give them an advantage on the B&H (as 387s will no doubt be prioritised for the Paddington-Reading-Didcot corridor), and they can then be used to send all the 165s/166s west (though that may have been already implied).

Predominantly that’s the plan.

 

[edwin_m]

EMU acceleration time to 50mph is typically half that of hydraulic / mechanical transmission DMUs as they can supply far more power at the wheel at low speeds, hence I'm not surprised by that comment.

Acceleration depends on tractive effort not power. At low speeds tractive effort depends on the weight on the powered axles and by the adhesion achieved, not on the power available, so acceleration will be better only if the electric transmission achieves much better adhesion to counteract the lower proportion of the weight that is on powered axles.

The available power starts limiting acceleration only when speed increases, so if the 769 has more useable power (in relation to its weight) than two 150s then it wll start to gain at higher speeds. But at these speeds the 769 in diesel mode will still have less acceleration than in electric mode because there amount of power from the diesels is less than what it can use from the wire.

 

[themiller]

Forgive me here, but wont they be expected to be tested at 110mph?! Now before you snort your derision towards me, you all know a train has to be capable of being safe at speeds over the allowed limit. Therefore if the train as a 319 is allowed at 100mph. Doesn't that theoretically mean that it should be tested at 10% over? Yes I know full well the only way it would ever do 110 is to drop it from the outer atmosphere, but would this mean it will be limited to 75 on both modes until it can be proven?

Doesn't that only apply to new trains? As these are already approved as EMUs, they should be OK.

 

[gingertom]

Doesn't that only apply to new trains? As these are already approved as EMUs, they should be OK.

these units will be carrying an extra 15 tonnes of equipment, it would make sense to make sure the brakes are up to the job. Am sure they are but there's always that wee bit of doubt so a test would be sensible.

 

[AM9]

these units will be carrying an extra 15 tonnes of equipment, it would make sense to make sure the brakes are up to the job. Am sure they are but there's always that wee bit of doubt so a test would be sensible.

Given that in EMU service they rarely actually reached 100mph with their 990kW of motor power, a test at whatever is acheivable on a 100mph line with OLE would probably prove the point.
Surely the 110% test is only practicable on modern ac motored designs where the service speed is achievable with some power in reserve.

 

[100andthirty]

I think you will find that they only have to test things that have changed. The electric system and the speed the trains can reach is part of the original Class 319 train which is already approved.

 

[driver_m]

Good luck trying to use that point though to get ASLEF to accept the sets if they haven't been properly tested. Doesn't matter if it takes forever to get to 100 with one, it's performance and characteristics are known as a 319. You can't send it into Lime St and expect it to behave the same, otherwise it could repeat the antics of 142 059. I wouldn't touch one with a bargepole if it had not been tested fully. It's not like you're fettling an engine to run in eco mode or changing the pantograph type. You're fundamentally changing it.

 

[AndrewE]

Good luck trying to use that point though to get ASLEF to accept the sets if they haven't been properly tested. Doesn't matter if it takes forever to get to 100 with one, it's performance and characteristics are known as a 319. You can't send it into Lime St and expect it to behave the same, otherwise it could repeat the antics of 142 059. I wouldn't touch one with a bargepole if it had not been tested fully. It's not like you're fettling an engine to run in eco mode or changing the pantograph type. You're fundamentally changing it.

I'm sorry to hear that reaction, if it's a 319 but just a bit slower off the mark on 25kV AC because of the weight of the diesel gubbins underneath then why reject it? It is still probably quicker than the diesels it replaces - and even if it's not, it still offers a better passenger environment.
I have been sat on a failed diesel-hydraulic rail grinder at the river bed after it couldn't manage the climb not long before the passenger service was due to start. That driver was really sweating, I can't imagine anything similar on a 769 (which can't be that much different to a fully-loaded 319) out of Lime St .

 

[AM9]

I'm sorry to hear that reaction, if it's a 319 but just a bit slower off the mark on 25kV AC because of the weight of the diesel gubbins underneath then why reject it? It is still probably quicker than the diesels it replaces - and even if it's not, it still offers a better passenger environment.
I have been sat on a failed diesel-hydraulic rail grinder at the river bed after it couldn't manage the climb not long before the passenger service was due to start. That driver was really sweating, I can't imagine anything similar on a 769 (which can't be that much different to a fully-loaded 319) out of Lime St .

I was about to post something about that. Sombody here has suggested that the fitting of two diesel engine/generators, fuel tanks and ancillaries increases the overall tare weight by about14 tonnes. the average passenger is probably around 70kg so that equates to about 200 passengers, that's not even filling every seat, (the class 319/4s seat 256 second class and about 32 first class). They have been plying the MML and BML for over 25 years carrying over 400 per unit in the peaks, which is about 28 tons weight.
The other thing is that in 2006, the class 319/4 units had their emegency brake pressure increased to the +12.5G standard. This together with the years of experience with them makes them pretty good candidates for safe operation with the additional weight of the mods. I would imagine that a comprehensive risk assessment would ensure a abbreviated clearance test programme.

 

[Bornin1980s]

Good luck trying to use that point though to get ASLEF to accept the sets if they haven't been properly tested. Doesn't matter if it takes forever to get to 100 with one, it's performance and characteristics are known as a 319. You can't send it into Lime St and expect it to behave the same, otherwise it could repeat the antics of 142 059. I wouldn't touch one with a bargepole if it had not been tested fully. It's not like you're fettling an engine to run in eco mode or changing the pantograph type. You're fundamentally changing it.

What was the problem with 142059?

 

[EE Andy b1]

What was the problem with 142059?

This was the problem....

https://www.urbanghostsmedia.com/2017/04/crashed-pacer-142059-manchester-victoria/

 

[AndrewE]

Good luck trying to use that point though to get ASLEF to accept the sets if they haven't been properly tested. Doesn't matter if it takes forever to get to 100 with one, it's performance and characteristics are known as a 319. You can't send it into Lime St and expect it to behave the same, otherwise it could repeat the antics of 142 059.

What was the problem with 142059?

This was the problem....https://www.urbanghostsmedia.com/2017/04/crashed-pacer-142059-manchester-victoria/

Apparently a 142 hit the stop-blocks at Lime St., but

The other thing is that in 2006, the class 319/4 units had their emergency brake pressure increased to the +12.5G standard. This together with the years of experience with them makes them pretty good candidates for safe operation with the additional weight of the mods.. I would imaging that a comprehensive risk assessment would ensure a abbreviated clearance test programme.

That's reassuring. Hopefully a fair test will reveal whether this is just scaremongering, or whether there might really be a risk. If there is then I thank the Union for highlighting it (& hope it gets sorted pdq,) if not then I look forward to the benefits soon to come.

 

[158820]

From Rail Operations Group website

[ROG have been appointed as test operator for the new class 769 ‘Flex’ hybrid multiple units. Testing commences in early November on the West Coast Main Line. ROG will also be delivering the new units to various locations around the UK. ]

 

[Bornin1980s]

This was the problem....

https://www.urbanghostsmedia.com/2017/04/crashed-pacer-142059-manchester-victoria/

Good grief! How did the driver survive that?

 

[big all]

with skid marks on his underpants

 

[Chris125]

Just come across this, showing some test running at the GCR:

 

[61653 HTAFC]

Hearing the "chug" of a diesel coming out of the same unit as the "hum" of electric traction motors will take some getting used to.

 

[big all]

made me laugh
exceleration seems quite good

 

[AM9]

Hearing the "chug" of a diesel coming out of the same unit as the "hum" of electric traction motors will take some getting used to.

On a video, the overall volume is really determined by the camera, it's placement and the surroundings, however, comparing the diesel engine sound with the well known sound of the DC traction kit is a better comparison. Interesting that when accelerating from standstill at a respectable rate, the DC-DC converters and the motor drive pinion whine (over about 10mph) can be clearly heard above the diesel.

 

[driver_m]

I'm sorry to hear that reaction, if it's a 319 but just a bit slower off the mark on 25kV AC because of the weight of the diesel gubbins underneath then why reject it? It is still probably quicker than the diesels it replaces - and even if it's not, it still offers a better passenger environment.
I have been sat on a failed diesel-hydraulic rail grinder at the river bed after it couldn't manage the climb not long before the passenger service was due to start. That driver was really sweating, I can't imagine anything similar on a 769 (which can't be that much different to a fully-loaded 319) out of Lime St .

You can't simply assume though, that everything will be alright. You.may not be aware that as a 221 driver for VTWC, that I can't drive an XC 221 set. (It has differences such as the missing tilt bars and various alterations). It might only be minor, and under BR, it wouldnt likely even be an issue, but the legal world we are in now, means it's just not an option. So a 769 which will have wildly varying driving techniques, an extra mode of power, very different abilities. It will have to be thoroughly tested for approval by the authorities . Mods are even included in this . Research Lime St .That 142 is far from the only thing to hit the blocks there .

 

[themiller]

With the extra weight acting on the bogies of the driving cars, I would have thought that the brake pressure on those bogies could be reset upwards to increase the braking effort thus (at least in some measure) offsetting the extra weight.

 

[AM9]

You can't simply assume though, that everything will be alright. You.may not be aware that as a 221 driver for VTWC, that I can't drive an XC 221 set. (It has differences such as the missing tilt bars and various alterations). It might only be minor, and under BR, it wouldnt likely even be an issue, but the legal world we are in now, means it's just not an option. So a 769 which will have wildly varying driving techniques, an extra mode of power, very different abilities. It will have to be thoroughly tested for approval by the authorities . Mods are even included in this . Research Lime St .That 142 is far from the only thing to hit the blocks there .

In terms of driver training, of course there will be specific training, maybe as a class 319 conversion.
As far as testing the class 769 in terms of it's suitability to run in service, I would expect a risk assessment to be prepared, identifying and new issues, - either from new equipment/modes or modifications that unintentionally affect the existing hardware. As has been posted above, Porterbrook selected the class 319/4 variant that had modifications to improve its braking capability which through intensive service fully- no overloaded with passengers, makes its reliability/performance a known quantity. It's strange that the BR MKIII body has long been praised as a sturdy and safe design yet there are prophecies of them folding up like the notorious Pacer event at Lime Street at the first opportunity. As a DEMU, the train will also use it's rheostatic braking for most service braking at speed, so the final/emergency (mechanical) brakes should not suffer from heavy use.
Of course the regular detractors here are looking for future jeopardy to wallow in but I suspect that Brush have broken the back of technical issues, and the project will now proceed, albeit delayed.
As far as the new trains on order go, (331s,195s etc.,) they are as yet unproven in service despite their manufacturers' exhortations, so whilst the 769s will be no racehorses, they should at least provide the required service levels.

 

[jopsuk]

From Rail Operations Group website

[ROG have been appointed as test operator for the new class 769 ‘Flex’ hybrid multiple units. Testing commences in early November on the West Coast Main Line. ROG will also be delivering the new units to various locations around the UK. ]

So you're saying all the "What if?" and "WELL ASLEF WON'T LIKE THAT" on here is nonsense and they will in fact be tested appropriately?

 

[Islineclear3_1]

Slightly OT but if my eyes weren't deceiving me, how was the unit able to pass all the signals at Danger ??

 

[Fincra5]

Slightly OT but if my eyes weren't deceiving me, how was the unit able to pass all the signals at Danger ??

I'd imagine as its likely to be testing on Single Line working (out of passenger services on the GCR) the signals aren't in use - and therefore are just ignored. (Can't imagine there's TPWS to deal with!)