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

[pemma]

The concept is a "last few miles" DMU, not one that can keep up on the mainline on diesel. The diesel engines would only be used on the mainline in the event of a power failure.

So they definitely won't be used on lines between Sheffield and Wakefield in that case.

 

[notlob.divad]

You are not going to need to power it at "full chaff" - take a look at the use-case. 100mph, or even 75mph, is completely unnecessary.

The concept is a "last few miles" DMU, not one that can keep up on the mainline on diesel. The diesel engines would only be used on the mainline in the event of a power failure.

Just because you don't need the top speed doesn't mean you don't need to be able to get the thing moving in the first place. It is the acceleration that will need the power, not the velocity. Currently we are talking about adding a double digit % increase in the total weight that is also going to need accelerating after every station irrespective of where the power is coming from.

 

[Domh245]

Erm, whatever they've shoved under the D-train, for one? Those rafts are designed for supplying a third-rail EMU to run at low speeds - sounds familiar here?

These units would not need to run at 100mph on diesel, let alone 125mph - the concept is for something that can keep up on the electrified mainline and then run onto low-speed branch lines. 60mph on diesel would probably be quite adequate.

The requirement is not for a 4-car direct Class 150 substitute, even if the result might look like one

There is a total of 600kW on a 230 propelling 60 tonnes of train (based on LU weights for 2 DMs) up to 60mph. Trying to use the same engines to propel 140 tonnes (w/o engines or fuel) would be comical at best bearing in mind that the current power output is 980kW and that's before you even start to draw power away from the engines for any other hotel services.

 

[sprinterguy]

A 150s engine (of which there are 1 per car) would output 213kW. There would then be some losses in the conversion to Electricity. Therefore to power a 319 at full chaff 4x247.5kW motors, you would need 4.6 of the engines in a 150. even if you allow for a lower top end power (if that is even possible) you are still looking at 4 engines which would take up the undercarriage of all 4 units of a 319. Which is not possible because there is stuff there already on the middle two.

Improved performance characteristics of modern engines means that an underfloor engine of comparable size to that fitted to a 150 can produce 400 - 500hp, as per the class 172 units which are towards the upper end of that range. Using a pair of Ford Transit engines in what I understand is a fairly compact arrangement will allow the class 230 to generate 400hp per car. As Neil Williams states, this trial is similar in application to the class 230.

The unit doesn't need to be particularly nippy on diesel power, but a power output of around 800hp per unit should be entirely sufficient for use on secondary and branch lines where speeds are unlikely to exceed 60mph.

 

[Bletchleyite]

But with the extra weight, they may not be able to run at 100mph on the OHLE either, and it will certainly put a dent into their acceleration profile.

I reckon you would get them to 100mph, they'd just take longer to get there. The acceleration is not noticeably different to the passenger with a full load as empty, and a full load of passengers, assuming 100 or so per coach as full and standing so a total of 400 per unit and an average 65 kilo passenger (as is used for lifts) that makes a full passenger load 26 tonnes on its own (I was surprised it was that high TBH - but I can't see a fault in the maths there). It makes less difference than you'd think.

The power output of the 230 is 300kW per car produced from 2 150kw underfloor generator sets. 319s have a total of 990kw of motor drive so you are looking at needing 6-7 of those same generator sets. Going for 6, you would have to get 3 generators into a very similar space that Vivarail have managed to fit 2. I am not saying it isn't possible, but there is certainly a technical challenge to over come.

As you won't need the metro-style acceleration of the 230, and you're similarly going for a low top speed so won't *need* 990kW, I'd suggest that the same layout as the 230 of two Transit-engine-based gensets on each of the two outer trailer coaches would work. And they're longer coaches, with far less underneath.

It sounds like a relatively easy job to me provided the power car and trailer car bodies are similar enough so can handle the extra weight.

 

[61653 HTAFC]

But with the extra weight, they may not be able to run at 100mph on the OHLE either, and it will certainly put a dent into their acceleration profile.

The power output of the 230 is 300kW per car produced from 2 150kw underfloor generator sets. 319s have a total of 990kw of motor drive so you are looking at needing 6-7 of those same generator sets. Going for 6, you would have to get 3 generators into a very similar space that Vivarail have managed to fit 2. I am not saying it isn't possible, but there is certainly a technical challenge to over come.

So hypothetically using the same Ford Duratorq engines as the 230, perhaps stacking them up above the floor behind each cab would be better?

Though if you're going above the floor, simply re-using engines which already exist (would that not bypass the emissions regulations?) would be better, such as all those lovely Valentas that are currently hidden in the disused bore of Standedge Tunnel?

 

[sprinterguy]

There is a total of 600kW on a 230 propelling 60 tonnes of train (based on LU weights for 2 DMs) up to 60mph. Trying to use the same engines to propel 140 tonnes (w/o engines or fuel) would be comical at best bearing in mind that the current power output is 980kW and that's before you even start to draw power away from the engines for any other hotel services.

Would the performance of a 4-car class 150 formation with an engine out be considered "comical", then? As that would be a similar sort of power to weight ratio.

 

[Bletchleyite]

Just because you don't need the top speed doesn't mean you don't need to be able to get the thing moving in the first place. It is the acceleration that will need the power, not the velocity.

It's actually both, and you can work on that with gearing (and the electrical equivalent).

My car will accelerate quickly in 1st gear but won't go any faster than about 25mph if that in that gear. It will not even start off in 5th gear.

Similarly, if you go for a lower top speed on diesel, you can use that power for acceleration instead.
--- old post above --- --- new post below ---

So hypothetically using the same Ford Duratorq engines as the 230, perhaps stacking them up above the floor behind each cab would be better?

Though if you're going above the floor, simply re-using engines which already exist (would that not bypass the emissions regulations?) would be better, such as all those lovely Valentas that are currently hidden in the disused bore of Standedge Tunnel?

If going above the floor and using van engines, the obvious answer would probably be two on each side under the pantograph with a central gangway, a bit like the well-proven Stadler FLIRT / GTW engine module. It isn't a nice place to sit anyway - noisy and claustrophobic - so no great loss on a unit that isn't going to be rammed and standing the whole time. And if you put them there you don't have to transmit the power very far to get it into the third-rail DC circuitry (which if you're building a hybrid OHLE/DMU unit is how you might as well do it, as all the existing switchgear etc would work - you'd just be whacking 750VDC into it a different way than through the shoes).
--- old post above --- --- new post below ---

Would the performance of a 4-car class 150 formation with an engine out be considered "comical", then? As that would be a similar sort of power to weight ratio.

It'd be more than adequate for the lines we're thinking of. These won't be running on diesel on the WCML unless the power is out, in which case anything that moves, however slowly, is better than nothing.

 

[sprinterguy]

But with the extra weight, they may not be able to run at 100mph on the OHLE either, and it will certainly put a dent into their acceleration profile.

Compared to the 75mph DMUs that currently work some of these services, I don't think that pathing a slightly heavier 319 running on electric power between Preston and Lancaster or Oxenholme is going to worry the train planners unduly.

I can't understand why you see a need for the power output on diesel to come close to matching the output on electric. Over sections of route where they can achieve higher speeds, they'll be running on electric power.

 

[Bletchleyite]

As an above-floor alternative, you could put them in the next car if putting them in the power car would make it too heavy. If there is going to be a glut of EMUs available soon, which there is, if that makes *that* car too heavy for the trailer bogies you could swap the bogies from another power car, making two spare EMUs into one good one.

TBH, this all sounds quite a lot less far-fetched than converting Tube stock - and I could see a prototype appearing quite quickly if it is indeed true. Did Shooter perhaps buy the wrong used EMUs up?

 

[Domh245]

Would the performance of a 4-car class 150 formation with an engine out be considered "comical", then? As that would be a similar sort of power to weight ratio.

Similar but not really. Your 4 car 150 has 850kW propelling 140 tonnes (including engines), whilst this bi-modal with 4 Vivarail gensets has 600kW propelling 140 tonnes (not including engines). Not to mention that the 150 has the advantage of a gearbox whilst the 319 wouldn't.

 

[Bletchleyite]

So they definitely won't be used on lines between Sheffield and Wakefield in that case.

They appear to be being conceptualised for the Windermere branch in relatively small numbers, so how did you get to using them there?

 

[sprinterguy]

Similar but not really. Your 4 car 150 has 850kW propelling 140 tonnes (including engines), whilst this bi-modal with 4 Vivarail gensets has 600kW propelling 140 tonnes (not including engines).

No, a 4-car 150 formation with an engine out produces 639kW.

Also for accuracy (though helping my argument none ) a 4-car class 150 is around 150 tonnes in weight (150/1s are a bit heavier than 150/2s), while a 4-car Bi-mode class 319 will likely be closer to 160.

 

[Bletchleyite]

Similar but not really. Your 4 car 150 has 850kW propelling 140 tonnes (including engines), whilst this bi-modal with 4 Vivarail gensets has 600kW propelling 140 tonnes (not including engines). Not to mention that the 150 has the advantage of a gearbox whilst the 319 wouldn't.

Electric transmission substitutes for a mechanical gearbox, effectively. You have a gearbox on a diesel engine because it has a relatively limited power band. An electric motor does not - it will give you maximum tractive effort it can at near enough any given rotational speed (within much wider limits).

Actually, thinking more, a 150 has hydraulic transmission - there are substantial heat losses when not running in direct drive, hence newer stock going back to mechanical transmission and some TOCs trying mechanical transmission on things like Class 158s. Electric transmission might actually prove *more* efficient and get more of that 600kW down onto the rail.

And again, your Class 150 needs to perform well up to 75mph - this doesn't.
--- old post above --- --- new post below ---

No, a 4-car 150 formation with an engine out produces 639kW.

I think his hasn't got an engine out

 

[notlob.divad]

It's actually both, and you can work on that with gearing (and the electrical equivalent).

My car will accelerate quickly in 1st gear but won't go any faster than about 25mph if that in that gear. It will not even start off in 5th gear.

Similarly, if you go for a lower top speed on diesel, you can use that power for acceleration instead.

But you are not comparing like for like, Yes you could change the gearing in a 319 as well if you really want and give you the acceleration, but my point is you need the power there in the first place, however you are going to distribute it.[/QUOTE]

 

[Bletchleyite]

But you are not comparing like for like, Yes you could change the gearing in a 319 as well if you really want and give you the acceleration, but my point is you need the power there in the first place, however you are going to distribute it.

Do some reading up on how electric motors work - I think you are still thinking of one as similar to a petrol or diesel engine with a limited power band - they are not like that - they offer "gearing" in their own right.

Consider one of the proposed Class 800s with the "last mile" diesel (one 750hp engine per 9-car unit feeding all the traction motors which usually get far more power from the 25kV) - by your understanding they should not be able to move, but by mine they would move adequately up to about 20mph or so, which is what they are intended to do.

 

[sprinterguy]

I think his hasn't got an engine out

Yeah, hence me pointing it out - Domh245's theoretical 150 formation is clearly more reliable than mine!

 

[61653 HTAFC]

As an above-floor alternative, you could put them in the next car if putting them in the power car would make it too heavy. If there is going to be a glut of EMUs available soon, which there is, if that makes *that* car too heavy for the trailer bogies you could swap the bogies from another power car, making two spare EMUs into one good one.

TBH, this all sounds quite a lot less far-fetched than converting Tube stock - and I could see a prototype appearing quite quickly if it is indeed true. Did Shooter perhaps buy the wrong used EMUs up?

The low number of motored axles has long been a criticism of the 317-322 family, when compared with both the PEP-based units (313-315) and the 323s. If this proposal also adresses that issue it has to be a good thing.

With engines above the floor, I'd expect there'd be restrictions on noise levels for passengers to be subjected to- so going behind the cabs would possibly mean less soundproofing required. As for getting the power generated to the motors, I assume you'd use the wiring already in place for the shoegear which is on the outer bogie of each driving trailer.

Apologies for the pedantry but the 230s are not and were not "Tube trains"! Whilst this project has much in common with the 230 scheme, they're aiming for quite different markets (or as a cynic might say, they're two similar solutions looking for quite different problems!).

 

[Bletchleyite]

Ah, if the shoes are on the driving trailers, I'd say that putting it all under the floor of the relatively empty driving trailers is probably the way to go - all you're basically needing to create is a reliable 750VDC genset of adequate power output and a means of bolting it under the floor, ideally with quick swaps possible using a forklift like the 230. Beyond that it's effectively a matter of plugging it in, replacing the shoegear. (A bit more complex if you want to keep the shoegear, but for the use case being discussed that is not necessary)

This really should not be a difficult job (notwithstanding the railway's usual ability to make things that aren't complicated more complicated than they need to be).

 

[notlob.divad]

I can't understand why you see a need for the power output on diesel to come close to matching the output on electric. Over sections of route where they can achieve higher speeds, they'll be running on electric power.

I am not. I have gone with the numbers I can easily look up. I accept that the won't need the same power which is why in each calc I have mentioned on here I have rounded the answer down. However there is also losses and other things to take into account. A 319 on OHLE has 4x247.5kW at the motor I was looking at about 900kW output of the generators to allow this plus the compressors for the doors / brakes. Plus the control systems / lights / heating etc etc. so the actual power available to turn the wheel will be significantly less anyway.

Add to that, comparisons with the D trains are slightly misleading given the weight differential of the starting point. 3 car 230 73.4 tonnes, 4 car 319 140.3 tonnes.

I am not stating that I need to match the output on diesel, but given all the other factors that need to be taken into account, you have to start with some numbers somewhere.

 

[Bletchleyite]

And, if you find you don't need it in the future because more wires have gone up, just unbolt it and chuck it in a warehouse as as spare!

 

[Domh245]

No, a 4-car 150 formation with an engine out produces 639kW.

Also for accuracy (though helping my argument none ) a 4-car class 150 is around 150 tonnes in weight (150/1s are a bit heavier than 150/2s), while a 4-car Bi-mode class 319 will likely be closer to 160.

I think his hasn't got an engine out

Yeah, hence me pointing it out - Domh245's theoretical 150 formation is clearly more reliable than mine!

Mea Culpa! I think I should probably read things more carefully.

 

[61653 HTAFC]

Ah, if the shoes are on the driving trailers, I'd say that putting it all under the floor of the relatively empty driving trailers is probably the way to go - all you're basically needing to create is a reliable 750VDC genset of adequate power output and a means of bolting it under the floor, ideally with quick swaps possible using a forklift like the 230. Beyond that it's effectively a matter of plugging it in, replacing the shoegear. (A bit more complex if you want to keep the shoegear, but for the use case being discussed that is not necessary)

This really should not be a difficult job (notwithstanding the railway's usual ability to make things that aren't complicated more complicated than they need to be).

The only issue I can see with putting the gensets under the driving trailers (and it certainly isn't a showstopper) is that as far as I know all mk3-based 2020-proof solutions thus far have placed the universal toilets in one of the driving cars- if there's motors and fuel tanks there then you've little room for water and waste tanks, so the loo needs to go somewhere else along with the tanks.

 

[notlob.divad]

Do some reading up on how electric motors work - I think you are still thinking of one as similar to a petrol or diesel engine with a limited power band - they are not like that - they offer "gearing" in their own right.

I'm an electrical engineer, I've got a pretty decent knowledge already thank you.

Consider one of the proposed Class 800s with the "last mile" diesel (one 750hp engine per 9-car unit feeding all the traction motors which usually get far more power from the 25kV) - by your understanding they should not be able to move, but by mine they would move adequately up to about 20mph or so, which is what they are intended to do.

So we are going to be running Oxenhome to Windermere at 20mph in normal service then? My understanding of a last mile concept is it is a rescue function, or to allow freight trains into unelectrified sidings. Not to be running the 11 miles to and from Oxenholme. It needs to provide enough power to give the torque to get the thing moving and up to a decent speed between stops.

 

[pemma]

They appear to be being conceptualised for the Windermere branch in relatively small numbers, so how did you get to using them there?

Leeds to Sheffield was suggested as a route further up the thread. Given it's a part electrified line and there is no official plan for them to be used on any route (Northern or with any other operator) I don't see why that route shouldn't be seen as an option.

Like I said earlier on I imagine any trial unit will only be used on fully electrified routes with Northern in case anything goes wrong when it's not running off the overheads, in the same way the IPEMU was trialed and like IPEMU the concept might not go any further.

 

[sd0733]

Just pulled up alongside a 319 so had a look at the driving vehicle under the floor. Between the bogies there appears to be 2x air tanks and 2 small electrical boxes which presumably have something to do with the doors as they are under them. Also a larger box nearer the inner end of the coach. But the rest of it is clear so if an engine raft could fit in the space between the doors and the bogie and the other the other side of the door then it seems pretty feasible at least for the space under there.

 

[Bletchleyite]

So we are going to be running Oxenhome to Windermere at 20mph in normal service then? My understanding of a last mile concept is it is a rescue function, or to allow freight trains into unelectrified sidings. Not to be running the 11 miles to and from Oxenholme. It needs to provide enough power to give the torque to get the thing moving and up to a decent speed between stops.

No, we're going to be doing it at about 50mph, so we only need enough power to get there at a reasonable rate. Not to run at 100mph. Coincidentally, that's probably going to be about the same amount of power as you need to move a 9-car 800 at 20mph

Crikey, if raw power was what we needed, the 185s wouldn't shut down an engine when running on the branch.

 

[D365]

As an above-floor alternative, you could put them in the next car if putting them in the power car would make it too heavy. If there is going to be a glut of EMUs available soon, which there is, if that makes *that* car too heavy for the trailer bogies you could swap the bogies from another power car, making two spare EMUs into one good one.

TBH, this all sounds quite a lot less far-fetched than converting Tube stock - and I could see a prototype appearing quite quickly if it is indeed true. Did Shooter perhaps buy the wrong used EMUs up?

No, this bogie swapping and trailer converting sounds way more far-fetched than simply slinging an engine under a lightweight ex-LU carriage. If I were you I would rather wait and see what news comes out of Loughborough, for all we know this is just as likely to be a total non-starter.

 

[Bletchleyite]

No, this bogie swapping and trailer converting sounds way more far-fetched than simply slinging an engine under a lightweight ex-LU carriage. If I were you I would rather wait and see what news comes out of Loughborough, for all we know this is just as likely to be a total non-starter.

The easiest way is going to be to sling an engine under the trailer cars. That will be easier than the D-train, as there is no need to work on crashworthiness, cabs etc, and you could just put the output from a 750VDC genset straight into the third rail circuits.

 

[D365]

The easiest way is going to be to sling an engine under the trailer cars. That will be easier than the D-train, as there is no need to work on crashworthiness, cabs etc, and you could just put the output from a 750VDC genset straight into the third rail circuits.

How many engines do you need though? Even if one engine was enough, and you swapped the bogies, the carriage superstructure would need a helluva lot of modification and recertification. And then there's the risk of introducing further reliability issues...