Could a bi-mode version of the 331s or 195s be possible as a follow on order?

[Bletchleyite]

Mod Note: Posts #1 - #12 originally in this thread.

I can see these rapidly growing market share on their routes due to the quality step change to such an extent that a larger order will be required, and given the age of the 156/158s it seems that a much bigger order would have been justified with longer term rolling delivery?

Not being familiar with the route though, and given the overall DMU shortage, it did strike me that it was odd to run Barrow - Manchester airport with so much under the wires. Wouldn't it make more sense to split the service at Lancaster or Preston to free up DMUs for diesel only routes? Unpopular with airport passengers of course, where a through train is especially helpful - but 80% plus people on my train were not going to the airport, though that might change with different times of day.

If there is such a second order, I hope CAF can offer a bi-mode. It might then make sense to order dedicated units for this most InterCity of Northern's routes, with additional luggage capacity and perhaps even a small First Class area.

 

[Greybeard33]

If there is such a second order, I hope CAF can offer a bi-mode. It might then make sense to order dedicated units for this most InterCity of Northern's routes, with additional luggage capacity and perhaps even a small First Class area.

The CAF website does offer a bi-mode traction option for the Civity platform (along with electric, diesel-mechanical, diesel-hydraulic, diesel-electric and battery-electric). But AFAIK there have been no orders for bi-modes to date.

Bear in mind that the baseline Civity configuration is an articulated unit to the continental loading gauge. I doubt that there would be room for diesel generators under the floor of the British 195/331 bodyshell. A generator plus traction motors would need more space than the 195's ZF transmission. A 755-like configuration, with full height generator compartments or pods, would probably be needed. So a loss of commonality with the 195 and 331.

Considering that several Northern Connect routes are partly electrified, I imagine Arriva would have evaluated the bi-mode option before selecting the diesel-mechanical traction package for the 195. Presumably the conclusion was that the total operating costs for a bi-mode would be higher than for running DMUs partly under the wires.

Now that Northern has a large fleet of 195s, the relative cost of adding a micro-fleet of bi-modes would be much higher than for a few more 195s. I cannot envisage Northern choosing that path unless offered sufficient additional subsidy to compensate.

 

[Bletchleyite]

Bear in mind that the baseline Civity configuration is an articulated unit to the continental loading gauge. I doubt that there would be room for diesel generators under the floor of the British 195/331 bodyshell. A generator plus traction motors would need more space than the 195's ZF transmission.

But isn't the Euro-Civity a low-floor unit as most are now? Do they put the gubbins at roof level (as I know some designs do)? If not, that means there will probably be more space under the UK unit.

 

[LOL The Irony]

Considering that several Northern Connect routes are partly electrified, I imagine Arriva would have evaluated the bi-mode option before selecting the diesel-mechanical traction package for the 195. Presumably the conclusion was that the total operating costs for a bi-mode would be higher than for running DMUs partly under the wires.

Now that Northern has a large fleet of 195s, the relative cost of adding a micro-fleet of bi-modes would be much higher than for a few more 195s. I cannot envisage Northern choosing that path unless offered sufficient additional subsidy to compensate.

Since Northern are only supposed to have 8 769's, it would probably be better to order 8 4 car 195's.

 

[Greybeard33]

But isn't the Euro-Civity a low-floor unit as most are now? Do they put the gubbins at roof level (as I know some designs do)? If not, that means there will probably be more space under the UK unit.

The baseline Euro-Civity is indeed a low floor articulated unit, with most of the electrical equipment mounted on the roof. Since a bi-mode does not actually exist, we can only speculate, but I imagine the diesel generators would go either on the roof, as on the Alstom Coradia Polyvalent, or in above floor pods, as on the Stadler FLIRT. The roof mounted configuration would not be feasible within the British loading gauge.

 

[Roast Veg]

The CAF website does offer a bi-mode traction option for the Civity platform (along with electric, diesel-mechanical, diesel-hydraulic, diesel-electric and battery-electric). But AFAIK there have been no orders for bi-modes to date.

Bear in mind that the baseline Civity configuration is an articulated unit to the continental loading gauge. I doubt that there would be room for diesel generators under the floor of the British 195/331 bodyshell. A generator plus traction motors would need more space than the 195's ZF transmission. A 755-like configuration, with full height generator compartments or pods, would probably be needed. So a loss of commonality with the 195 and 331.

On a 4 car 331 there is an enormous amount of space under the trailer car - more than enough and more than a 319. I don't know what voltage the DC bus along the train is rated at but I'd be very surprised if a generator couldn't supply it.

 

[Greybeard33]

On a 4 car 331 there is an enormous amount of space under the trailer car - more than enough and more than a 319. I don't know what voltage the DC bus along the train is rated at but I'd be very surprised if a generator couldn't supply it.

But a 769 has gensets under two trailer cars. Does a 331/1 have enough room for a second genset under the pantograph trailer, in addition to the transformer and other electrical kit? Even if so, a bi-mode 331 would only have two 390kW diesel engines, the same as a 769. A 769 is claimed to have performance on diesel comparable to a 150. I cannot find the weight of a 331, but it is likely greater than a 319, being a longer unit. And the aircon would absorb some of the engine power, so performance would be worse than a 769.

A 4-car 195 would have four 390kW diesels, one under each car - more than twice the available power of the hypothetical bi-mode!

 

[deltic08]

But a 769 has gensets under two trailer cars. Does a 331/1 have enough room for a second genset under the pantograph trailer, in addition to the transformer and other electrical kit? Even if so, a bi-mode 331 would only have two 390kW diesel engines, the same as a 769. A 769 is claimed to have performance on diesel comparable to a 150. I cannot find the weight of a 331, but it is likely greater than a 319, being a longer unit. And the aircon would absorb some of the engine power, so performance would be worse than a 769.

A 4-car 195 would have four 390kW diesels, one under each car - more than twice the available power of the hypothetical bi-mode!

Would a 331 bimode need to be as powerful as a 150 when it is being used off the wire where linespeed is usually lower?

 

[Roast Veg]

But a 769 has gensets under two trailer cars. Does a 331/1 have enough room for a second genset under the pantograph trailer, in addition to the transformer and other electrical kit? Even if so, a bi-mode 331 would only have two 390kW diesel engines, the same as a 769. A 769 is claimed to have performance on diesel comparable to a 150. I cannot find the weight of a 331, but it is likely greater than a 319, being a longer unit. And the aircon would absorb some of the engine power, so performance would be worse than a 769.

A 4-car 195 would have four 390kW diesels, one under each car - more than twice the available power of the hypothetical bi-mode!

There is certainly far less space under the PTSO, but the space is non-zero, as you can see in the following picture. Definitely enough room to survey whether it could be done with an underfloor reshuffle.

You are correct that with only two 390kW motors it would be very anaemic on diesel. Is there a particular reason why multiple or larger engines could not be used, other than CAFs datasheets?

 

[Greybeard33]

Would a 331 bimode need to be as powerful as a 150 when it is being used off the wire where linespeed is usually lower?

A bi-mode that had worse acceleration and hill climbing capability than a Sprinter, off the wires, would be very limited as to suitable routes. I doubt it would be acceptable for the Furness line. Even on the Windermere branch, it might struggle to keep to the timetable.

 

[Greybeard33]

You are correct that with only two 390kW motors it would be very anaemic on diesel. Is there a particular reason why multiple or larger engines could not be used, other than CAFs datasheets?

There are few engines available that are suitable for underfloor mounting and comply with current emissions requirements. The 195 uses a MTU engine and the 769 a MAN, but both are rated at 390kW. The Hitachi 801/802 has a larger MTU 700kW engine, but that is installed under a longer carriage with a higher floor than the 331. The Stadler Class 755 uses 480kW Deutz engines, but these are installed above floor in a separate power car.

I do not think there would be room for a genset under the 331 driving motor cars, nor for more than one under each trailer car. So I believe 2 x 375kW would be the realistic limit for underfloor engines with the existing 331/1 bodyshells.

 

[Geoff DC]

Scania pack a V8 730hp Euro 6 under a standard highway truck - pretty tight I would say

 

[samuelmorris]

The 3-car 755 only has two of the engine pods filled, resulting in 960kW total for a 65m train. Acceleration in that config is rated at 0.7ms^-2 which isn't exactly stellar, but isn't bad compared with the units they could be replacing. Three GUs in a 4-car 'Bimode 331' would result in 1170kW for a 95m train, so a little less, but perhaps manageable. The question is whether there's room to fit a third GU. Probably not without a complete redesign in which case there's little point, CAF may as well offer something closer to the European-style like Stadler did instead.

 

[js1000]

Bear in mind that the baseline Civity configuration is an articulated unit to the continental loading gauge. I doubt that there would be room for diesel generators under the floor of the British 195/331 bodyshell.

Now that Northern has a large fleet of 195s, the relative cost of adding a micro-fleet of bi-modes would be much higher than for a few more 195s. I cannot envisage Northern choosing that path unless offered sufficient additional subsidy to compensate.

Eversholt as the owner of the units will be the ones who decide. Looking at it from a cold, heart business perspective - I find it completely unthinkable Eversholt would have ordered the 195s without them being 'bi-mode convertible/ready' as they'll have to probably move away from diesel generation at some stage over the next 30 years of its predicted operation.

 

[LOL The Irony]

Well Northern want to order more new trains. https://www.railmagazine.com/news/network/northern-considering-options-for-more-new-trains

As the first CAF Class 195 diesel and ‘331’ electric multiple units enter traffic with Northern, the operator is already discussing the possibility of ordering more new trains to meet a potential capacity challenge.

Senior Northern sources told RAIL on June 28 that the operator believes the new trains will entice more people onto its services, and that within two years - once all 101 new trains are in service - there could be overcrowding.

Asked by RAIL if it would be better to wait for the next Northern franchise before ordering new trains (it is due to begin in 2025), the source said: “Waiting for the new franchise would mean trains not entering traffic in 2028 or 2029.”

 

[big all]

There is certainly far less space under the PTSO, but the space is non-zero, as you can see in the following picture. Definitely enough room to survey whether it could be done with an underfloor reshuffle.

You are correct that with only two 390kW motors it would be very anaemic on diesel. Is there a particular reason why multiple or larger engines could not be used, other than CAFs datasheets?

unrealistic and optimistic

maybe a decent battery pack instead off a third engine that could give a decent power boost for excceleration and a limited bit off movement off the wires

 

[squizzler]

I think that after the new trains for the MML are ordered we will see a pause in bi-mode acquisitions as the industry as a whole ponders their success. Meanwhile, despite the savvy sounding cynicism of this forum's 'experts', the pendulum inexorably swings back towards electrification.

Unpausing electrification in the North opens the gates to an almost unlimited supply of existent electrics. A rolling programme of electrification means a rolling opportunity to use more electric units as traffic grows. And these can be longer units, because @GRALISTAIR points out, electrification usually means a line upgrade and that includes longer platforms.

 

[Greybeard33]

Eversholt as the owner of the units will be the ones who decide. Looking at it from a cold, heart business perspective - I find it completely unthinkable Eversholt would have ordered the 195s without them being 'bi-mode convertible/ready' as they'll have to probably move away from diesel generation at some stage over the next 30 years of its predicted operation.

Bi-modes would still be diesels. If/when there is an environmental requirement to get rid of diesels, both bi-modes and DMUs will have to be withdrawn or retractioned. I expect Eversholt will have priced the risk of early withdrawal into its lease rates for the 195s. It would be rash to assume that it would be economically viable to retraction them in 2040, when they will be 20 years old.

 

[JamesT]

Bi-modes would still be diesels. If/when there is an environmental requirement to get rid of diesels, both bi-modes and DMUs will have to be withdrawn or retractioned. I expect Eversholt will have priced the risk of early withdrawal into its lease rates for the 195s. It would be rash to assume that it would be economically viable to retraction them in 2040, when they will be 20 years old.

The speech by the former minister https://www.gov.uk/government/speeches/lets-raise-our-ambitions-for-a-cleaner-greener-railway which prompted all this only talks about getting rid of diesel-only trains.
It also talks about newer diesels being less polluting than older ones as an improvement. The ban on sales of petrol/diesel cars also allows for hybrids to continue as I understand it.
I think the bi-modes are relatively safe from that deadline as they're clearly less polluting than running pure diesels under the wires and provide better air quality in the most built up areas where there's more likely to be electrification.
I think the 195s also have a fairly long life ahead of them. There will still be many routes that require self-powered rolling stock and the priority will be replacing the older dirtier DMUs. As long as the overall emissions of the rail industry fall they will be able to justify running 195s to something more like their natural lifespan. Also, given the pollution inherent in building new things, it may be overall more environmentally friendly to keep it running.

 

[krus_aragon]

Bi-modes would still be diesels. If/when there is an environmental requirement to get rid of diesels, both bi-modes and DMUs will have to be withdrawn or retractioned.

A bi-mode can be cleaned up by running it under the wires. The same won't work for diesels.

 

[Greybeard33]

A bi-mode can be cleaned up by running it under the wires. The same won't work for diesels.

You are suggesting costly bi-modes should be procured now, then used as EMUs in, maybe, 20 years time, when diesel is banned?

It might be preferable overall to procure cheaper DMUs now, then replace them with brand new EMUs in 2040. Who can predict how technology might develop over the next 20 years?

 

[krus_aragon]

You are suggesting costly bi-modes should be procured now, then used as EMUs in, maybe, 20 years time, when diesel is banned?

It might be preferable overall to procure cheaper DMUs now, then replace them with brand new EMUs in 2040.

You're right, a straight DMU may well be cheaper. But if one is looking to reduce diesel use during those 20 years, and you have a partially electrified network, the bi-modes should be considered, because you can "clean it up" immediately by running on electric where possible. The Bi-mode gives flexibility, at a price.

(Note that I agree with TfW's choice to order a diesel-only long-distance fleet: there's currently so little electrified track on their network that there'll be plenty of diesel-only routes for them to operate in the foreseeable future. With the presence of overhead wires in many parts of the North of England, I expect that the choice isn't so obvious, but I don't have the on-the-ground knowledge to start second-guessing those decisions.)

Who can predict how technology might develop over the next 20 years?

Indeed. But we need to make decisions for the short- and medium-term term in the meantime.

 

[apk55]

DEMUs are generally more efficient than a DMU and can normally get more performance out of a smaller diesel (unless a multi speed gearbox transmission is provided and these have generally proved unreliable in rain railway operation.) This would certainly mean less CO2 (and other emissions as well) over a DMU.
A bimode can be considered as a DEMU with the addition of a Transformer rectifier or third rail front end. If circumstances change they could easily be either converted to an EMU or use an alternative power source such as battery or fuel cell

 

[edwin_m]

DEMUs are generally more efficient than a DMU and can normally get more performance out of a smaller diesel (unless a multi speed gearbox transmission is provided and these have generally proved unreliable in rain railway operation.) This would certainly mean less CO2 (and other emissions as well) over a DMU.
A bimode can be considered as a DEMU with the addition of a Transformer rectifier or third rail front end. If circumstances change they could easily be either converted to an EMU or use an alternative power source such as battery or fuel cell

172s use multi-speed transmission and are pretty reliable as far as I know. The 195s and 196s are similar.

I guess it's a matter of cost and space. Cost because a gearbox and associated equipment is probably cheaper than an alternator and traction motors, and space because DMUs tend to have engines under each car so there's not much space for the transformer.

 

[samuelmorris]

172s use multi-speed transmission and are pretty reliable as far as I know. The 195s and 196s are similar.

I guess it's a matter of cost and space. Cost because a gearbox and associated equipment is probably cheaper than an alternator and traction motors, and space because DMUs tend to have engines under each car so there's not much space for the transformer.

In the case of West Midlands they're not bad, but not quite up to the standard of their hydraulic predecessors. 19k MTIN vs 20k for 170s at West Midlands, but 7k on both LO and Chiltern versus 15k for the 168s and 19k for the 378s. That said, seemingly the hydraulic transmission on 170s isn't up to the short distance services Northern have used them on thus far (4k MTIN), so mechanical transmission may prove more effective in such areas.

 

[AM9]

... Indeed. But we need to make decisions for the short- and medium-term term in the meantime.

The 'greenest' solution would be to keep whatever existing DMUs there are that can be extended for the next (say) 10-15 years service and use them to bridge current shortage. The net lifetime pollution of these legacy units would be no more than for newly acquired stock like the 195s.
The already procured 195s (along with the more modern stock like some of the Turbostars) would then provide a gradually declining diesel-only fleet for the lines that will stay un-electrified indefinitely.
All this pressure for buying yet more new diesels is just kicking the can further down the road.
As far as a bi-mode version of the 195s goes that would be starting from the wrong place. They have mechanical drives to the axles so would need complete replacement of the bogies. Starting from something like the 331s is the only practical way ahead. The Aventra, (and maybe the Siemens Verve range) could form the basis of new bi-mode trains.
Just as all mainline DC trains introduced since the early naughties have been required to be convertible for ac power, all new diesel multiple units should be readily convertible to bi-mode, (either electro-diesel or battery-electric).

 

[Greybeard33]

The 'greenest' solution would be to keep whatever existing DMUs there are that can be extended for the next (say) 10-15 years service and use them to bridge current shortage. The net lifetime pollution of these legacy units would be no more than for newly acquired stock like the 195s.

The Stage IIIB compliant engines of the 195s emit far less particulates and nitrogen oxides than those of the legacy DMUs, which predate the emissions requirements. Less difference in carbon dioxide emissions, but even those are improved by the more efficient engines and the mechanical gearboxes versus hydraulic transmissions.

 

[AM9]

The Stage IIIB compliant engines of the 195s emit far less particulates and nitrogen oxides than those of the legacy DMUs, which predate the emissions requirements. Less difference in carbon dioxide emissions, but even those are improved by the more efficient engines and the mechanical gearboxes versus hydraulic transmissions.

That may be true but the long-term push to remove ic driven vehicles from everywhere is because of their CO2 emissions which affect the whole planet. So, unless the IIIB engines emit less than half of the CO2 of older units for the same amount of work, my statement in post #26 above is true.

 

[Greybeard33]

It might become economically viable to synthesise carbon neutral diesel fuel, from biomass and/or renewable energy, instead of refining it from fossil oil. But that would not address the health hazards of exposure to diesel engine exhaust emissions and so is not seen as a long term solution for decarbonisation of the railway.

 

[apk55]

I have always wondered on how much more a DEMU costs relative to a DMU. In the past it was probably quite significant because of the high costs of commutator motors and generators but with with modern 3 phase drives mass produced for the vast EMU market the different will be less. As well as being more more efficient overall (ie fuel used to run a service) I would expect them to have lower maintenance requirements. One of the advantages of a DEMU is that you can make an easily swap-able engine module that can be swapped for a new unit at service time (think class 203)

Another advantage with a DEMU is that it can be converted to hybrid operation as well bi mode operation. In many services (particularily on local stopping services) the load factor (average power output/ maximum power output) could be as low as 20% meaning that the diesel engine running inefficiently on part power and burning fuel when idling.