Possible Class 159/158 conversation to bi - modal

[Domh245]

Whatever is ordered must be 125mph capable.

For the MML expresses, yes, but for 158/159 replacement you certainly don't

 

[MarkyT]

I thought it worth mentioning the power supply limitations of the infrastructure again. Desiros all have to run with their power limited artificially today, so where's the extra current coming from for yet more trains running on the third rail? However with 25kV conversion off the table in the foreseeable future presumably those overdue substation feeder grid renewals will be back on again soon, perhaps offering an opportunity for further strengthening at the same time. And new capacity built in for some extensions?

I don't see how you could do an electric transmission conversion job on these units without a complete strip-out of all equipment under the body and possibly bogie replacements as well. Maybe the bogie frames and suspension elements could be reused with complete factory remanufacture, incorporating electric traction motor drive, or is there a cardan drive shaft that could be linked to a body suspended motor, Voyager style, instead of the hydraulic drive train? Perhaps this kind of work is not THAT different to that proposed for the 442s. A while ago I read a suggestion elsewhere that for these, one possibility might be to motorise multiple Mk 3 trailers in these sets, as modern traction motors of the types fitted recently to the 455s could be small and light enough to mount in the rebuilt, currently unpowered, BT 10 bogies. If this design could take traction motor(s), then perhaps a P4-4A (the powered bogie of the two on each car of the 158/9 units) might be able to do so as well by some means, once shorn of its current transmission equipment.

 

[Class313:)]

Could u bi-mode a 442?

 

[MarkyT]

Could u bi-mode a 442?

Possibly as part of a major rebuild, but they're all promised to the Portsmouth Direct expresses under SWR I thought, where they won't need diesels.

 

[js1000]

Bi Mode conversions of 158/9s is a joke. Sadly what I can see them finding feasible is the hybrid 319s or worse hybridising 455s. This would be a downgrade of what are very well suited units for the routes they serve.

The 319s can't even keep up with the timetable on the Manchester Airport stoppers!

 

[Agent_Squash]

The 319s can't even keep up with the timetable on the Manchester Airport stoppers!

Don't worry, it's only a few years until the Grayling realises it'll be political suicide to let new trains sit in the sidings and all the 319s are scrapped...

 

[D365]

Don't worry, it's only a few years until the Grayling realises it'll be political suicide to let new trains sit in the sidings and all the 319s are scrapped...

Aside from the poor acceleration characteristic, they're doing their job. Do you think Grayling's really going to pay any heed to the north?

 

[delt1c]

Interesting thing here is that it appears that electric or bimode is associated with traction motors. Lets take tachnology a step further, is it possible to have electric motors providing power to the hydraulic systems? Maybach units were used for both electric and hydraulic transmissions

 

[tbtc]

It's vastly, vastly easier to convert EMUs to bi-modes by just adding a generator or two (be that under or above floor) than it is to convert DMUs to bi-modes (with the need to add all sorts of electrical gubbins etc).

That's my understanding too.

Plus, we'll have hundreds of "spare" EMU coaches in a few years time, but about the only DMU coaches "spare" will be Pacers/ 153s that are uneconomic to convert to modern accessibility standards.

So, if we do nothing, the 158/159s still have several years of use. The onus should therefore be on whether we can effectively/efficiently convert 319s/ 321s/458s/ 707s (etc). Plus, obviously, finding something suited to the Salisbury services that the SWR 158/159s do...

...so 90mph is necessary but 125mph would be a waste (especially as there's your "crumple zone" space to consider)...
...you need something that can work in multiple (since you need 200m trains at Waterloo but that's generally a waste at Exeter)...
...you need something that can work single services on the "six" - since it'd be uneconomical to have a separate fleet for those services...
...the 158/159s could certainly get snapped up at Northern or Wales'n'Borders...

...but we'll continue to see suggestions for filling the route with unsuitable trains (Voyagers, Meridians etc)

 

[D365]

Lets take tachnology a step further, is it possible to have electric motors providing power to the hydraulic systems?

Vastly inefficient and even more cost-ineffective.

 

[Agent_Squash]

Aside from the poor acceleration characteristic, they're doing their job. Do you think Grayling's really going to pay any heed to the north?

It was an optimistic point of view... it’s unlikely to happen.

 

[delt1c]

Hydraulics work on a pressure basis, so why would an electric motor providing the source of power

 

[Bletchleyite]

You could body mount a large traction motor feeding into the existing gearboxes and final drive, but there would be no point putting it through the hydraulic transmission as it would duplicate that function and waste energy.

 

[Bletchleyite]

Hydraulics work on a pressure basis

Not Sprinter transmissions. They essentially work by a large "fan" turning the oil which turns another "fan" connected to the wheels, in very simplified terms.

 

[MarkyT]

You could body mount a large traction motor feeding into the existing gearboxes and final drive, but there would be no point putting it through the hydraulic transmission as it would duplicate that function and waste energy.

Like Voyagers, class 91s and ATP-P power cars. There may be others. Less unsprung weight than axle hung motors.

 

[The Ham]

...but we'll continue to see suggestions for filling the route with unsuitable trains (Voyagers, Meridians etc)

The only way that you could use 22x's on the route would be if all the following were met:
- if they were 10 coach units (i.e. 2 end coaches and 8 middle coaches) which ran end to end (as this would give you a comparable capacity to the current 8 coach 158 trains).
- the wires had reached Yeovil so that you could provide lots of capacity on EMU's
- the calling pattern was XX:00 EMU from Yeovil, XX:30 DMU from Exeter to Yeovil with a change to EMU to Waterloo, XY:00 EMU from Yeovil, XY:30 was a 10 coach 22x from Exeter.
- the Salisbury 6 services could be run by EMU as the wires had reached there.

Without doing so there either wouldn't be enough capacity in the 22x's or there wouldn't be enough 22x's to run all the services. Likewise you'd end up with micro fleets.

 

[D365]

Like Voyagers, class 91s and ATP-P power cars. There may be others. Less unsprung weight than axle hung motors.

Those are mechanical Cardan shafts, not hydraulic gearboxes.

 

[MarkyT]

Those are mechanical Cardan shafts, not hydraulic gearboxes.

I'm not a hydraulic expert, but I thought the final drive from the output side of the transmission to axle gearboxes also typically used mechanical cardan shafts, and what I thought Bletchleyite meant was substituting a body mounted traction motor where the hydraulic transmission module is today, reusing the mechanical cardan shafts and gearboxes.
http://www.westernchampion.co.uk/loco-d1015-technical.php

 

[Bletchleyite]

I'm not a hydraulic expert, but I thought the final drive from the output side of the transmission to axle gearboxes also typically used mechanical cardan shafts, and what I thought Bletchleyite meant was substituting a body mounted traction motor where the hydraulic transmission module is today, reusing the mechanical cardan shafts and gearboxes.
http://www.westernchampion.co.uk/loco-d1015-technical.php

Yes, that's what I meant. The hydraulic "gearbox" would be removed.

 

[edwin_m]

Yes, that's what I meant. The hydraulic "gearbox" would be removed.

If the engine stays in the same place, then both the alternator and the traction motor would have to go into the space vacated by the hydraulics. I think that's a pretty tall order.

Some bogies, such as the BR series 3 used first on the PEP units and most recently on Electrostars and Turbostars, have used either traction motors or cardan shaft drive in the same basic design. However I'm not sure if a bogie can be converted from one to the other, as they may have different mountings etc. As far as I'm aware the T4 bogie used on the 158/159 has only ever been used with a cardan drive or unpowered.

 

[MarkyT]

If the engine stays in the same place, then both the alternator and the traction motor would have to go into the space vacated by the hydraulics. I think that's a pretty tall order.

Some bogies, such as the BR series 3 used first on the PEP units and most recently on Electrostars and Turbostars, have used either traction motors or cardan shaft drive in the same basic design. However I'm not sure if a bogie can be converted from one to the other, as they may have different mountings etc. As far as I'm aware the T4 bogie used on the 158/159 has only ever been used with a cardan drive or unpowered.

Agree, assuming the engine and transmission are placed as close as possible to each other which seems highly likely. That suggests a more significant rebuild beneath the frame with a new gen-set raft placed further away or the engine 'turned round' in its existing position with the alternator connected at the other end.

 

[Billy A]

Not Sprinter transmissions. They essentially work by a large "fan" turning the oil which turns another "fan" connected to the wheels, in very simplified terms.

Yes, nearly all diesel/hydraulics use multiple torque converters and fluid couplings and switch between them to change gear, although there's a trend towards conventional bus type automatic gearboxes.

 

[hwl]

If I (BEng, MEng, CEng) were engineering Bi-mode conversion for 159s assuming 455s can be canabalised for parts...

The current power bogies have both axles driven driven by a cardan shaft and hydraulic gearbox, the engine isn't actually that close to the driving bogie - just look for the exhaust system on photos of the left hand side of the driving car (the power bogie is at the inner end). There is plenty of space for a 3 phase 300kW alternator, off the shelf alternators that will bolt straight on to either of the 159 engine types are between 95cm and 115cm long depending on precise specification and manufacturer and between 600-700kg, single phase would be bigger, heavier and less efficient so 3 phase is the best option. The potential space issue is where to find space for the traction electronics boxes in their current shape so some reworking might be required there but then it will be anyway see below...

The simple solution for 3rd rail pick is to fit the shoe gear from the 455 to the outer (trailing bogies) on the driving cars, if that is slightly tricky (step design of the 159s might be an issue) then may be a bogie swap from the 455s.

The question then is how many power bogies, the 350hp units should be fine with just 2 power bogies (350hp engines total shaft hp 1050, traction motor 1000hp total and the hotel power and compressors will be more than the difference) but more spirited performance on the 3rd rail area might be wanted so 3 power bogies make sense especially for the 400hp units (1200hp shaft - 1500hp traction motors. So assuming 3 power bogies the traction electronics will need re-engineering and splitting up for just 2 TMs rather than 4 which would actually make it easier to fit in.

Then there is plenty of DC bus and control cabling to add.

With 30x 3car 159s and presumably (might acquiring a few more make sense?) 10x2 car 158s that comes to 110 motor bogies so it would presumably make sense to use all the 455/7s for parts and then 12 units from one of the other sub classes?

 

[edwin_m]

The 455s are only rated for 75mph. If 100mph units such as the 319 use the same power bogie then they probably have extra dampers as the trailing bogies do. I'm not sure how easy those are to retrofit (does the lower-speed version include the necessary mountings?). Also are the AC traction motors good for the higher speed, or could this be solved by re-gearing?

 

[Kneedown]

Why? 100mph would be quite adequate.

Not on the Midland Main Line it wouldn't. Majority of linespeed in excess of 100mph with a decent bit 120-125mph!

 

[Kneedown]

For the MML expresses, yes, but for 158/159 replacement you certainly don't

I read it as the expresses under discussion, not the local fleet.

 

[Bletchleyite]

Not on the Midland Main Line it wouldn't. Majority of linespeed in excess of 100mph with a decent bit 120-125mph!

Confused - whyever would we be running bi-mode Class 158/9s on the MML? They would be completely unsuitable in just about every way. Class 801 derivatives would be far better (even if I hate the seats!)

 

[Domh245]

I read it as the expresses under discussion, not the local fleet.

I'd been talking about the wholesale replacement of the SWR DMU fleet with a fleet of bimodes, when @The Ham pointed out that EMT and XC are likely to be ordering Hitachi AT300 bimodes. I then pointed out that they don't need to be 125mph units for those roles though, as the line speed is never more than 100 and that an alternate bi-mode offering from Stadler or CAF would be more appropriate - so the production capacity of Hitachi wouldn't be a concern. I do agree with you about the MML solution, whatever it is does need 125mph capability, preferably on diesel!

 

[MarkyT]

If I (BEng, MEng, CEng) were engineering Bi-mode conversion for 159s assuming 455s can be canabalised for parts..

Thank you for that very comprehensive, positive comment. The proposal is clearly not as ridiculous as initial responses suggested. Whether it's worth it is another matter, but the 158/9s are still fairly modern looking and very reliable units, with (IMO) a nice Intercity style passenger cabin environment, especially the SW examples, so as long as changes could be incorporated cost-effectively an electric transmission conversion, with the bi-mode 3rd rail pick up and on-board energy storage possibilities that could offer might be a good investment for another decade or two's service.

 

[D365]

The proposal is clearly not as ridiculous as initial responses suggested.

Well... it is. The 769 is a far simpler conversion, look at the issues that’s been facing. The 321 rebuild has had its own teething troubles, and Angel Trains has given up on 317722 entirely.