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Right Away

Cost Difference - Hydraulic v Electric Transmissions

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Member 18B's post relating to loco weights prompted in me a response, however on reflection, I though it better to have it's own thread.

 

It would be interesting to compare the cost differencial between main line diesel hydraulic and diesel electric locomotives, predominantly Type 4, Type 3 and Type 2 classes. The sums would include initial outlay and running/maintenance figures. For those of us who experienced the introduction of main line diesel traction as one of the results of the so-called "Modernisation Plan", this transition was beheld by many as the ultimate in railway traction in the late Fifties.

 

Could it have been that the BR (WR) accountants were grossly misled when the merits of hydraulic transmissions were presented and decided upon. In what some might consider in hindsight, an almost indecent haste to rid their Region of the "old fashioned" traction, one wonders why the WR powers that were, were given such a free hand. An enormous burden to the taxpayer, the railway, with such desperate financial implications would appear in retrospect to have had little control over such matters. Many front rank steam engines, having incurred the expense of very recent heavy repairs were dispensed with in comparatively short time.

 

The "Warships", "Westerns" , "Hymeks" and the North British Tyoe 2s, all of comparively short operational duration, have all given us enthusiasts a rich traction history over which to ponder (and model) and as such we would have been all the poorer had the never been introduced.

 

Summing up, the United States had developed reliable electric transmissions for their railroads decades before.

 

 

 

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And the Germans had developed reliable hydraulic transmissions, so I guess there was a case for trying both.  Is this a case, like other diesel classes of the time, where large numbers were ordered before the relative merits of each class had been demonstrated? 

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I think this topic has been discussed before but I could be mistaken.  Initially on paper, diesel hydraulics had higher horsepower, gave better performance over diesel electrics plus saving on weight which pleased the PW department no end.

 

The problem came as the power units and transmission had to be imported or built under license which at the time, the West German Mark was strong against the pound which pushed the costs up.

 

Even though the US had used electric transmission for over 20 years, Southern Pacific and to a small extent, the Denver and Rio Grande experimented with MK diesel hydraulics in the 60’s and at they lasted only 6 years at most.  Not sure if this is true but they were usually relegated to trailing units as loco crews we’re wary of a spinning cardan shaft spinning under pressure underneath their seats lol.

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1 hour ago, Right Away said:

Summing up, the United States had developed reliable electric transmissions for their railroads decades before.

 

The US, or rather Electromotive, had set about developing electric transmission right from the beginning, to the exclusion of pretty well all else. Then, the priorities of wartime production gave EMD a huge head start over the other builders, a lead that, in essence, they never lost. After that, it becomes a case of why bother with anything else? Electric transmission is simple compared to hydraulic.

 

Jim

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Posted (edited)
On 06/03/2019 at 21:25, jools1959 said:

I think this topic has been discussed before but I could be mistaken.  Initially on paper, diesel hydraulics had higher horsepower, gave better performance over diesel electrics plus saving on weight which pleased the PW department no end.

 

The problem came as the power units and transmission had to be imported or built under license which at the time, the West German Mark was strong against the pound which pushed the costs up.

 

Even though the US had used electric transmission for over 20 years, Southern Pacific and to a small extent, the Denver and Rio Grande experimented with MK diesel hydraulics in the 60’s and at they lasted only 6 years at most.  Not sure if this is true but they were usually relegated to trailing units as loco crews we’re wary of a spinning cardan shaft spinning under pressure underneath their seats lol.

On Paper hydraulic transmissioned locomotives had a very very favourable advantage with tractive effort, its unfair to compare the hydraulic locomotives on horsepower to say a brush 4 because the hydraulics had two engines.....there was in traction a very very interesting article that BR could have potentially drastically reduced the class 56 order (i think talked about eliminating the Romanian built 56s off the order) had they thought about retaining some of the westerns displaced from the western region.

 

Transmission power however also had higher inefficiencies at the higher speed as well, and fuel consumption compared to a sulzer or an EE was inferior.

 

In fact foster yeoman considered taking on surplus westerns at the time as well.....

 

However you are forgetting they key issues that westerns and most hydraulics had was that no transmission capable was capable of more than 1500ish hp at the time and for a while after (hence why westerns were twin engined) class 35s were 1700hp but this was a different transmission....and also as a result of restricted bodyspace.....none of the westerns could have ETH....which is what eventually finished them off....

 

having 2 engines.....two transmissions....i would have said made them more expensive than there electric transmission counterparts.

 

Edited by pheaton

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Posted (edited)

The railway still has mainline diesel hydraulics, Tampers such as Matissa, drive is hydrostatic,  the diesel engine runs at full revs when in motion,  the diesel engine drives a large oil  pump which feeds a hydraulic out and back  loop.  final traction drive is by  hydraulic axle mounted traction motors. Power control is by a diverter  valve which diverts hydraulic fluid from the  hydraulic out and back loop  into the traction motors.

Tampers are by Plasser & Thuerer, ( built in Austria)   Matissa built in Switzerland.

 

The Warships and Hymeks  described as hydraulic,  but could they be described as  were diesel mechanical transmission with a torque convertor "clutch"  with their need to physically change gear?

Edited by Pandora
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On 06/03/2019 at 21:07, Right Away said:

Member 18B's post relating to loco weights prompted in me a response, however on reflection, I though it better to have it's own thread.

 

It would be interesting to compare the cost differencial between main line diesel hydraulic and diesel electric locomotives, predominantly Type 4, Type 3 and Type 2 classes. The sums would include initial outlay and running/maintenance figures. For those of us who experienced the introduction of main line diesel traction as one of the results of the so-called "Modernisation Plan", this transition was beheld by many as the ultimate in railway traction in the late Fifties.

 

Could it have been that the BR (WR) accountants were grossly misled when the merits of hydraulic transmissions were presented and decided upon. In what some might consider in hindsight, an almost indecent haste to rid their Region of the "old fashioned" traction, one wonders why the WR powers that were, were given such a free hand. An enormous burden to the taxpayer, the railway, with such desperate financial implications would appear in retrospect to have had little control over such matters. Many front rank steam engines, having incurred the expense of very recent heavy repairs were dispensed with in comparatively short time.

 

The "Warships", "Westerns" , "Hymeks" and the North British Tyoe 2s, all of comparively short operational duration, have all given us enthusiasts a rich traction history over which to ponder (and model) and as such we would have been all the poorer had the never been introduced.

 

Summing up, the United States had developed reliable electric transmissions for their railroads decades before.

 

 

 

 

The main decision making on loco purchase  was via several BTC committees, most notably the Technical Committee and the Supply Committee. These discussed potential purchases and made recommendations to the full meeting of the Commission.  Papers with costs, results of tenders etc would be submitted in advance by the Supplies department and the CME's department usually as a joint exercise. I am not sure how much involvement the accounting staff on the Western Region would have had, probably not a great deal. All the relevant documentation is at the National Archives Kew.

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Posted (edited)

Some of what you are asking about is covered in David N Clough's excellent book "Hydraulic versus Electric".  Building costs per loco for some classes are given.  e.g.

Type 3

D6700 £84000 

D7000 £79730  - £87950

Type 4

D1000 £115000 - £136000

D1500  £111000 -£125000

 

For comparison the last 9Fs built cost £33497 each.

 

 

Edited by asmay2002
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Posted (edited)

That the merkans had developed effective diesel electric power decades before the 1955 plan diesels were ordered is not really relevant to the UK situation; our restricted loading gauge and axle load limitations prevented us from having electric transmission locos on the American model, and loop/siding lengths prevented the multiple unit lashups common over there.  Simply put, American diesels were too big and heavy for British use, and the Ivatt twins were a very creditable accomplishment!

 

It is possible, in my view, that the results obtained from testing steam locomotives on the rollers at Rugby, which were very influential when it came to specifying the power requirements of the Plan diesels, were fundamentally flawed and that steam was measured as not giving out the horses at the railhead that it really was.  This would explain the ordering of the 2,000hp class 40s to replace 8P power on the WCML, which it failed to adequately do; the ECML went up to 3.300hp Deltics to replace their 8Ps, and 2,700 47s to replace the A3s.  This is a subjective view of my own and I have no hard evidence to back it up, but it seems to me to explain a lot of what went wrong.  On the WR, 2,200hp Warships were supposed to be better than 1,800hp KIngs, but had to be caned to death to match 7P Castle performances.  There's a feeling that ever more (but still insufficiently) powerful locos were being ordered to meet the traffic's demands, and that not until the 3.000+hp Deltics and the 25kv AL series electrics appeared was this achieved.

 

The choices were basically between diesel electrics that were huge and heavy (40, 44/5/6) because of the lumpy generators and hydraulics that were lighter and smaller but needed two engines as the transmissions couldn't handle more than 1,500hp each except for Hymeks, which came too late to make a difference.  The big diesel electrics had more room on board for retrofitted equipment and were better at stopping heavy unbraked freight trains, and the hydraulics were arguably designed too small and light for some work and could not be retrofitted with air brakes (except Westerns) or eth/air conditioning equipment.  

 

Keeping the hydraulics to one region to examine their performance closely was probably a good idea!

Edited by The Johnster

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44 minutes ago, The Johnster said:

That the merkans had developed effective diesel electric power decades before the 1955 plan diesels were ordered is not really relevant to the UK situation; our restricted loading gauge and axle load limitations prevented us from having electric transmission locos on the American model, and loop/siding lengths prevented the multiple unit lashups common over there.  Simply put, American diesels were too big and heavy for British use, and the Ivatt twins were a very creditable accomplishment!

 

It is possible, in my view, that the results obtained from testing steam locomotives on the rollers at Rugby, which were very influential when it came to specifying the power requirements of the Plan diesels, were fundamentally flawed and that steam was measured as not giving out the horses at the railhead that it really was.  This would explain the ordering of the 2,000hp class 40s to replace 8P power on the WCML, which it failed to adequately do; the ECML went up to 3.300hp Deltics to replace their 8Ps, and 2,700 47s to replace the A3s.  This is a subjective view of my own and I have no hard evidence to back it up, but it seems to me to explain a lot of what went wrong.  On the WR, 2,200hp Warships were supposed to be better than 1,800hp KIngs, but had to be caned to death to match 7P Castle performances.  There's a feeling that ever more (but still insufficiently) powerful locos were being ordered to meet the traffic's demands, and that not until the 3.000+hp Deltics and the 25kv AL series electrics appeared was this achieved.

 

The choices were basically between diesel electrics that were huge and heavy (40, 44/5/6) because of the lumpy generators and hydraulics that were lighter and smaller but needed two engines as the transmissions couldn't handle more than 1,500hp each except for Hymeks, which came too late to make a difference.  The big diesel electrics had more room on board for retrofitted equipment and were better at stopping heavy unbraked freight trains, and the hydraulics were arguably designed too small and light for some work and could not be retrofitted with air brakes (except Westerns) or eth/air conditioning equipment.  

 

Keeping the hydraulics to one region to examine their performance closely was probably a good idea!

 

We did approach General Motors to build locos but they declined on account of the very small numbers required. 

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14 hours ago, slilley said:

 

We did approach General Motors to build locos but they declined on account of the very small numbers required. 

This is a very good illustration of the point; GM were happy to accept small orders for their standard product F series, but the redesign that would have been needed to make the loco suitable for British conditions in the mid 50s, which might have resulted in an order for over a thousand locos, would have made them too expensive even at that volume.  If (and it's not a small if) that is such a loco could have been produced; my personal opinion is that GM or any US manufacturer would have found difficulty in getting anything British over 1,200hp or under 120 tons successfully into service.

 

They got the hang of building British locos eventually though, with the advent of smaller, lighter, generators.

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Posted (edited)

With regard to the figures quoted by Asmay 2002 above, the difficulty is that these represent tender prices from different manufacturers at different times for different production quantities i.e. they are not necessarily like for like costs. I seem to recall the book- Diesel Hydraulics of the Western Region-compared the costs of the NBL type 2 hydraulics and electrics (i.e. similar quantities from the same factory) and the hydraulics were a few £000 less. Given that the locos had the same engine and were otherwise broadly similar it suggests that hydraulic transmissions permitted a lower initial cost.

With regard to ongoing costs I don't believe BR had sufficiently accurate costing systems in the 1960's to make a proper decision. The lighter weight of the hydraulic locos should have resulted in lower track costs and possibly lower fuel. One would think a loco with two engines would need more maintenance than a single engine loco, but this wouldn't apply to types 1-3. I believe the hydraulic loco engines were relatively reliable-at least compared to the 47's which had to be down rated and the Brush type 2's which had the engines all replaced. It seemed mad spending money on reengining the Brush type 2's and transfer many to the Western to replace the Hymeks, when the Hymeks were much more able and lighter. Better to have kept the Hymeks and scrapped the lardy Brushes, saving the reengining cost.

I've never been convinced that the class 52's couldn't have provided electric heat/power. Space would have been available from removing the train heat boiler/tanks etc and I seem to recall the type2's for the Edinburgh-Glasgow push pull service had a separate generator installed. Again it seemed mad to withdraw the 52's, which were paid for and train crew and fitters trained on, to spend money on buying new 56's

 

Edited by David Bromley

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Under pressure to modernise and to speed up its services, the Western Region believed the most important factor was the fitting of automatic continuous brakes to the bulk of freight rolling stock. This, they believed, would eliminate the need to have the very heavy locomotives that were necessary to stop unfitted freight trains. (Brian Reed, Diesel-Hydraulic Locomotives of the Western Region/D&C) They believed that diesel-hydraulics had an advantage in much quicker acceleration and the smaller, lighter hydraulics based on the successful German V200 design were seen as offering those advantages. The BTC, however, wanted heavyweight locomotives to compare directly with the heavyweight diesel-electrics which were on order, so the WR got the D600 'Warships'. The subsequent 80ton D800 'Warships' must have been seen, at the time, to offer huge advantages over the 130-plus tons EE and BR/Sulzer diesel-electrics but history repeated itself. Just as the superior 7ft gauge lost out to 4ft 81/2in because there was so much more of the 'narrow' gauge, so the diesel-hydraulics as a minority were destined to lose out against the hundreds of 16-wheelers that were eventually built. (CJL)

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Except that the rest of the world had already gone for, and stuck with, diesel electric transmission, with only the Germans developing hydraulic transmission on any scale. That doesn't say that electric transmission was technically superior to hydraulic, or vice versa, but the operators thought it better overall.

 

Jim

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On 12/03/2019 at 01:28, The Johnster said:

This is a very good illustration of the point; GM were happy to accept small orders for their standard product F series, but the redesign that would have been needed to make the loco suitable for British conditions in the mid 50s, which might have resulted in an order for over a thousand locos, would have made them too expensive even at that volume.  If (and it's not a small if) that is such a loco could have been produced; my personal opinion is that GM or any US manufacturer would have found difficulty in getting anything British over 1,200hp or under 120 tons successfully into service.

 

They got the hang of building British locos eventually though, with the advent of smaller, lighter, generators.

 

I think the decision to buy British built diesel locomotives was primarily political to provide what we now call a direct stimulus British locomotive builders and to provide a showcase for potential export orders to Commonwealth countries.

 

 GM, General Electric and Alco were exporting and manufacturing large numbers of American designed locos under-license in the Commonwealth and South American since the mid-1950s. All three companies had developed light weight and compact designs to suit local conditions, GM & Nohab (Sweden) tendered to supply locos to the Ulster Transport Authority & Great Northern Railway (Board) in the early 1950s.

 

While Australia and New Zealand railway operators initially implemented a buy British policy, the GM G-12 export model quickly became the standard NZR main line locomotive following engine problems with the English Electric DF (basically a 1500hp  narrow gauge version of the EE Class 40). Victoria became a GM state, New South Wales GM & Alco, while Tasmania & Queensland remained loyal to English Electric.

 

Interestingly Nohab produced a European version of GM F Series under license in Sweden during the mid-1950s, which basically became a standard type of diesel locomotive outside of  France, Germany and Italy. These locos including the NSB Di 3 https://en.wikipedia.org/wiki/NSB_Di_3 would have fitted within British Railway's weight limits and could have been modified to fit the British loading gauge. 

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6 hours ago, dibber25 said:

Just as the superior 7ft gauge lost out to 4ft 81/2in because there was so much more of the 'narrow' gauge

That's a highly questionable statement to throw in as an aside, but not for this topic. 

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Posted (edited)
On 11/03/2019 at 12:28, The Johnster said:

This is a very good illustration of the point; GM were happy to accept small orders for their standard product F series, but the redesign that would have been needed to make the loco suitable for British conditions in the mid 50s, which might have resulted in an order for over a thousand locos, would have made them too expensive even at that volume.  If (and it's not a small if) that is such a loco could have been produced; my personal opinion is that GM or any US manufacturer would have found difficulty in getting anything British over 1,200hp or under 120 tons successfully into service.

 

They got the hang of building British locos eventually though, with the advent of smaller, lighter, generators.

 

Alco/GM and EMD proved themselves capable of building 1,600bhp 110 ton locos on six axles in 1953 to British loading gauge, even designing them with provision for vacuum brakes. They built a total of 96 between them. Mind you they were ordered by the American Government so possibly money no object...

 

https://en.wikipedia.org/wiki/ALCO_MRS-1

 

https://www.psrm.org/trains/diesel/us-air-force-2104/

Edited by Titan
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On 28/03/2019 at 01:49, John M said:

 

I think the decision to buy British built diesel locomotives was primarily political to provide what we now call a direct stimulus British locomotive builders and to provide a showcase for potential export orders to Commonwealth countries.

 

 GM, General Electric and Alco were exporting and manufacturing large numbers of American designed locos under-license in the Commonwealth and South American since the mid-1950s. All three companies had developed light weight and compact designs to suit local conditions, GM & Nohab (Sweden) tendered to supply locos to the Ulster Transport Authority & Great Northern Railway (Board) in the early 1950s.

 

While Australia and New Zealand railway operators initially implemented a buy British policy, the GM G-12 export model quickly became the standard NZR main line locomotive following engine problems with the English Electric DF (basically a 1500hp  narrow gauge version of the EE Class 40). Victoria became a GM state, New South Wales GM & Alco, while Tasmania & Queensland remained loyal to English Electric.

 

Interestingly Nohab produced a European version of GM F Series under license in Sweden during the mid-1950s, which basically became a standard type of diesel locomotive outside of  France, Germany and Italy. These locos including the NSB Di 3 https://en.wikipedia.org/wiki/NSB_Di_3 would have fitted within British Railway's weight limits and could have been modified to fit the British loading gauge. 

 

There are documents in the National Archives at Kew which show that GM were approached at the start of the Pilot Scheme to build locomotives. They declined on the grounds of insufficient numbers.  There were also discussions in the 1970s regarding American built locos at the time the whole Class 56 procurement exercise was happening.

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17 hours ago, slilley said:

 

There are documents in the National Archives at Kew which show that GM were approached at the start of the Pilot Scheme to build locomotives. They declined on the grounds of insufficient numbers.  There were also discussions in the 1970s regarding American built locos at the time the whole Class 56 procurement exercise was happening.

 

It would be understandable if GM declined to build a batch of Pilot Scheme locos if there was an expectation to set up an assembly plant in the UK or manufacture components in the UK. 

 

Its likely GM would have agreed to a British builder or a British Railways workshop assembling Pilot Scheme locos under license in a similar manner to Nohab or Clyde Engineering.

 

Whether British Railways could have agreed to a licensing arrangement at the time is another matter.

 

During the 1960s GM supplied engines to CIE to re-engine the Irish Metrovicks during the late 1960s, the conversion programme was successful, although GM initially had reservations about supplying the engines. 

 

Internationally GM tended to set up licensing arrangements with local builders to build locos using components supplied from the United States. Often locos are specials to suit local operating and climatic conditions and  produced in similar numbers to the Pilot build.

 

 

 

 

 

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BR were happy to allow licensing for the Warship Maybach engines, so I can't see why they wouldn't have for a US manufacturer.  But the Maybach experience was not a successful one...

 

 

 

 

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Their engines certainly seem to have been a good deal more successful than many of the UK designed engines of the period.

 

Jim

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As mentioned above, the CIE 'A' class were re-engined due to the poor reliability of their Crossley 2-stroke engine - the same (or similar) as those in our Co-Bos. By all accounts, the rest of the Metro-Vic traction package was pretty good - it was the engine that was the weak link.

 

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As seems generally to have been the case with all of the earlier British diesel locomotives, the weaknesses lay either in the engines themselves, or the mechanical connection between them and the generator. 

 

Jim

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21 hours ago, The Johnster said:

BR were happy to allow licensing for the Warship Maybach engines, so I can't see why they wouldn't have for a US manufacturer.  But the Maybach experience was not a successful one...

 

 

 

 

As far as I know, no British manufacturer held a licence for GM engines. Bristol Siddeley had the Maybach licence, NBL one for MAN, and of course Vickers for Sulzer. The BTC themselves were not into engine manufacture. As I have said previously GM were approached and declined on the grounds of the small number of orders. They were also approached at the time of the Class 56 procurement exercise, but that came to nothing.

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On 30/03/2019 at 03:47, slilley said:

 

There are documents in the National Archives at Kew which show that GM were approached at the start of the Pilot Scheme to build locomotives. They declined on the grounds of insufficient numbers.  There were also discussions in the 1970s regarding American built locos at the time the whole Class 56 procurement exercise was happening.

It seems odd that GM declined, on the basis of 'insufficient numbers'. Surely they knew that the potential was there, for several 1000 locomotives?

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