1955 Diesel Locos

[6Gman]

I've been doing some research on 1955 traffic patterns and loco workings and would be grateful for any info on the use of diesel locos at the period:

Ivatt locos 10000 and 10001 were based at Camden (along with 2 of the three SR locos - 10201/2). I know they were used on the WCML, including Scottish and Liverpool trains at various times, and the Ivatts sometimes double-headed. But does anyone know what they were typically used on in summer '55?

The other SR loco - 10203 - was at Nine Elms. Any ideas of its use?

10100 - the Fell loco - was at Derby and, I believe, was sometimes used through the Peak District to Manchester. Any ideas on its normal use?

10800 - the curious 800hp beast - was at Rugby, having previously been on the SR, and worked to/from Peterborough.

The 2 gas turbines were at Old Oak and I think mostly worked Bristol trains.

Thanks for any further info available.

 

[randyrippley]

According to http://extra.southernelectric.org.uk/features/historical-features/watexdieselops.html

10203 entered traffic based at Nine Elms in April 1954 and was initially subject to performance tests as it was fitted with a Mk II engine developing 2000 bhp at 850 rpm. 10000/1 and 10201/2 were fitted with Mk I versions of 750 rpm rated at 1600 and 1750bhp respectively. Using steam locomotive designations, the power classifications were 6P/5F for 10000/1 and 10201/1 and 7P/6F for 10203.

All five pioneer locomotives moved to Camden for West Coast main line duties in April 1955 never to return to SR metals but the machines had already verified the EE engine. ........

 

[Taunton]

The principal diesels of the period, of which there were several hundred by 1955, were of course diesel shunters.

The Gas Turbines were, spasmodically, used on Paddington to Bristol trains, out of Old Oak depot. I understand they were never regular operationally, and always went along with a development engineer when running. From the go it was apparent that they were a poor equivalent for diesels. 18000 was at least run from time to time; 18100, which used a different fuel, did very little mileage. One wonders how on earth Hawksworth talked the GWR directors into it all in the immediate post-war austerity era. Both locos were ordered by the GWR but not delivered until well into BR times.

Starting 18000 must have been a challenge. It had a battery starter motor which started up a diesel engine, possibly something from a lorry. This then started the turbine, I presume through some form of diesel-electric drive. The turbine started with aviation jet fuel (kerosene), once running it changed over to heavy bunker fuel, as used in ships. This fuel, notably, was also used in the turbines the Union Pacific built in the USA some years later. It was also the fuel used in the steam loco oil firing fiasco just a few years before, and indeed in a 57xx oil-fuelled tank loco trial at Old Oak in the latter part of the 1950s, which possibly shared the fuelling tank there. It must have been a right nuisance to have three types of fuel on 18000. It could also shunt itself at low speed with the auxiliary diesel, and apparently did so from Old Oak to Paddington, only starting the turbine at departure.

18000 was nicknamed "Kerosene Castle", which is a mistake for the mainstream fuel it used. 18100 apparently used kerosene throughout, and fuel cost was even worse.

 

[Gloster]

Two points from Volume 5 of Roger Harris’ The Allocation History of BR Diesels & Electrics:

10800 started 1955 at Plaistow for the Tilbury lines before moving to Rugby around February.

18100 is supposed to have been in store at Dukinfield Wagon Works throughout 1955.

 

[coppercapped]

The principal diesels of the period, of which there were several hundred by 1955, were of course diesel shunters.

The Gas Turbines were, spasmodically, used on Paddington to Bristol trains, out of Old Oak depot. I understand they were never regular operationally, and always went along with a development engineer when running. From the go it was apparent that they were a poor equivalent for diesels. 18000 was at least run from time to time; 18100, which used a different fuel, did very little mileage. One wonders how on earth Hawksworth talked the GWR directors into it all in the immediate post-war austerity era. Both locos were ordered by the GWR but not delivered until well into BR times.

Starting 18000 must have been a challenge. It had a battery starter motor which started up a diesel engine, possibly something from a lorry. This then started the turbine, I presume through some form of diesel-electric drive. The turbine started with aviation jet fuel (kerosene), once running it changed over to heavy bunker fuel, as used in ships. This fuel, notably, was also used in the turbines the Union Pacific built in the USA some years later. It was also the fuel used in the steam loco oil firing fiasco just a few years before, and indeed in a 57xx oil-fuelled tank loco trial at Old Oak in the latter part of the 1950s, which possibly shared the fuelling tank there. It must have been a right nuisance to have three types of fuel on 18000. It could also shunt itself at low speed with the auxiliary diesel, and apparently did so from Old Oak to Paddington, only starting the turbine at departure.

18000 was nicknamed "Kerosene Castle", which is a mistake for the mainstream fuel it used. 18100 apparently used kerosene throughout, and fuel cost was even worse.

At the time these locomotives were proposed and ordered the gas turbine was a very new machine and in the aviation world was opening new vistas of power and speed. The Gloster Meteor became the first Allied aircraft to be used in combat in the Second World War, entering service in 1944. It was an era of rapid developments in technology and people were trying out gas turbines in many different guises, look at, for example, Rover's JET1 of 1950. I can quite see that the gas turbine would appeal to Hawksworth as he was starting to evolve away from the Churchwardian standards of design and construction.

It wasn't obvious at the time that the decisions were made that gas turbines for land transport, except for certain niche products such as the US's M1 Abrams tank, would be a dead end.

But if one doesn't try, one doesn't know.

To return to 6Gman's original point - if the Railway Executive had not been so focussed on steam locomotives in 1948 and had spent the design and development effort it expended on the BR 'Standard' range of steam locomotives on developing the Ivatt and Raworth/Bulleid machines further there would have been more main line diesel locomotives around in 1955.

Maybe, just maybe, some of the real lemons of the Modernisation Plan would not have been built and BR's finances might have looked a bit healthier.

 

[Taunton]

Maybe, just maybe, some of the real lemons of the Modernisation Plan would not have been built and BR's finances might have looked a bit healthier.

The USA was of course well ahead by this time with dieselisation, some railways had fully changed over by then. This did not stop them having their own "lemons" - for example, anything built by Baldwin, in a close comparison to North British in a onetime top steam loco builder who just didn't make it in the transition.

 

[52290]

As a train spotter in Leyland in 1955 I used to see 10000/1 frequently on the Royal Scot. They always worked in tandem sharing duties with Duchesses. 10201/2 were also seen but less frequently. They also worked in tandem. 10203 always worked alone I seem to remember it was a regular on the up Midday Scot, as was the lone 71000.

 

[6Gman]

As a train spotter in Leyland in 1955 I used to see 10000/1 frequently on the Royal Scot. They always worked in tandem sharing duties with Duchesses. 10201/2 were also seen but less frequently. They also worked in tandem. 10203 always worked alone I seem to remember it was a regular on the up Midday Scot, as was the lone 71000.

Many thanks. Just the sort of detail I was searching for.

 

[delt1c]

Many thanks. Just the sort of detail I was searching for.

Just thinking aloud, what MU system was fitted to 10000/1 and 10201/2 were they compatible and were the Ivats ever run in MU/ Tandem with the SR machines ?

 

[52290]

Just thinking aloud, what MU system was fitted to 10000/1 and 10201/2 were they compatible and were the Ivats ever run in MU/ Tandem with the SR machines ?

I never saw that happen.

 

[delt1c]

I never saw that happen.

Never saw or heard of it either , but wondering if it ever happened

 

[Bevan Price]

I've been doing some research on 1955 traffic patterns and loco workings and would be grateful for any info on the use of diesel locos at the period:

Ivatt locos 10000 and 10001 were based at Camden (along with 2 of the three SR locos - 10201/2). I know they were used on the WCML, including Scottish and Liverpool trains at various times, and the Ivatts sometimes double-headed. But does anyone know what they were typically used on in summer '55?

The other SR loco - 10203 - was at Nine Elms. Any ideas of its use?

10100 - the Fell loco - was at Derby and, I believe, was sometimes used through the Peak District to Manchester. Any ideas on its normal use?

10800 - the curious 800hp beast - was at Rugby, having previously been on the SR, and worked to/from Peterborough.

The 2 gas turbines were at Old Oak and I think mostly worked Bristol trains.

Thanks for any further info available.

Not sure of the exact years, whilst on the Southern, 10201/02/03 were all used on Waterloo to Exeter or Bournemouth line expresses.

10000/01 also spent time on the Southern in 1953 & 1954.
Cannot remember the date, but the first time I saw 10001, it was working a London Euston to Blackpool service .

10100 spent much of its short life waiting for repairs, and demonstrated that trying to use a mechanical transmission on a 2000 hp diesel loco was a bad idea. On the occasions it actually worked, it was used on the MML.

10800 was a North British predecessor of Class 16, and apparently just as unreliable. Indeed, based on the performance of 10800, I can only wonder why somebody decided BR needed Class 16.

 

[Wyrleybart]

To return to 6Gman's original point - if the Railway Executive had not been so focussed on steam locomotives in 1948 and had spent the design and development effort it expended on the BR 'Standard' range of steam locomotives on developing the Ivatt and Raworth/Bulleid machines further there would have been more main line diesel locomotives around in 1955.

Maybe, just maybe, some of the real lemons of the Modernisation Plan would not have been built and BR's finances might have looked a bit healthier.

Funny you should say this, I had a quick shufty through the excellent work if Simon Lilley in his new book on the class 33s today. Simon mentioned that the class were not built with AWS, so it had to be fitted retrospectively. Now I now the SR, despite having a huge traffic density, were not a big user of AWS, but were not many of the BR standard steamers fitted with AWS ?
Certainly seems to me that the higher echelons BR weren't too joined up.

 

[randyrippley]

Funny you should say this, I had a quick shufty through the excellent work if Simon Lilley in his new book on the class 33s today. Simon mentioned that the class were not built with AWS, so it had to be fitted retrospectively. Now I now the SR, despite having a huge traffic density, were not a big user of AWS, but were not many of the BR standard steamers fitted with AWS ?
Certainly seems to me that the higher echelons BR weren't too joined up.

What would have been the point of fitting it?
As you say, the SR weren't great users of it, while the main out-of-region running would have been on the Western Region, who used a different system anyway. Extra cost for something that had no use and was just another thing to go wrong and fail the loco.
Remember: the more safety check systems you have, the higher the probability something will fail

 

[Irascible]

It wasn't obvious at the time that the decisions were made that gas turbines for land transport, except for certain niche products such as the US's M1 Abrams tank, would be a dead end.

But if one doesn't try, one doesn't know.

It's a pretty terrible choice for the Abrams too, their range is awful.

The problem with gas turbines for land use is they have a very small window for efficient operation - on a ship or an aircraft, or a powerplant thats fine and theres also room to fit considerable external cooling, but obviously not much use for a car or these particular rail installations. I did wonder why no-one ever tried using four ( as an example ) turbines & igniting them in series as individual throttle notches. APT-E had four per powercar but I think they all worked in parallel? in the early days of gas turbines that might have worked out a little better, for simple reasons of experience if nothing else.

The Railway Executive should maybe have just stsndardized on some existing steam designs for urgent replacements - resisting the urge to improve things - & gone all-in on standard diesels instead - we'd have had a couple of decades of probably horrendously unreliable traction, but I bet still better availability than steam. Also by the 80s when they needed replacing perhaps we'd have been able to sustain our native capacity better...

What would they have ordered though - 1950s traffic patterns were so different to even a decade on.

 

[etr221]

Funny you should say this, I had a quick shufty through the excellent work if Simon Lilley in his new book on the class 33s today. Simon mentioned that the class were not built with AWS, so it had to be fitted retrospectively. Now I now the SR, despite having a huge traffic density, were not a big user of AWS, but were not many of the BR standard steamers fitted with AWS ?
Certainly seems to me that the higher echelons BR weren't too joined up.

What would have been the point of fitting it?
As you say, the SR weren't great users of it, while the main out-of-region running would have been on the Western Region, who used a different system anyway. Extra cost for something that had no use and was just another thing to go wrong and fail the loco.
Remember: the more safety check systems you have, the higher the probability something will fail

The original plans for BR AWS installation - in the late 1950s - included the SR SW main lines from Waterloo to Bournemouth and Exeter - which was comparable with what was planned further north. In the same timescale (c1959 on), many steam locos (SR and other) were fitted (wholly or partially - whatever that meant) with AWS equipment.

So I would have expected AWS fitment to have been a standard feature for new motive power from then on.

 

[DelW]

According to "35 Years of Main Line Diesel Traction" by Colin Marsden, published in 1982:

10100: "During mid-1954, No 10100 suffered a major failure while hauling a train, which necessitated the locomotive's return to Derby Locomotive Works, where it remained for the next 12 months, before being repaired. In 1955, No 10100 was used in association with tractive effort tests on the Settle and Carlisle route, all of which proved to be very successful. From 1955, No 10100 worked a variety of passenger and freight trains on the Midland Region, and proved to be fairly reliable."

10800: "From February 1955, No 10800 was used on the Birmingham - Norwich route as well as on various freight workings, finally ending up parked outside Doncaster locomotive works awaiting a decision on its future."

 

[6Gman]

The original plans for BR AWS installation - in the late 1950s - included the SR SW main lines from Waterloo to Bournemouth and Exeter - which was comparable with what was planned further north. In the same timescale (c1959 on), many steam locos (SR and other) were fitted (wholly or partially - whatever that meant) with AWS equipment.

So I would have expected AWS fitment to have been a standard feature for new motive power from then on.

I wonder if it meant that the visual indication was included but not the bell/horn (or vice-versa)? Listening out for the aural indication might be tricky on a steam footplate?

 

[Taunton]

I wonder if it meant that the visual indication was included but not the bell/horn (or vice-versa)? Listening out for the aural indication might be tricky on a steam footplate?

Never a problem on the GWR steam footplate for the previous half-century

That's why it was a whacking great bell and hooter. It would be off-topic for me to, again, give a view on the implementation of this on the BR Britannia footplate which led to the (also 1955, November) accident on the WR at Milton, you can search for that here.

The Railway Executive should maybe have just standardised on some existing steam designs for urgent replacements - resisting the urge to improve things - & gone all-in on standard diesels instead - we'd have had a couple of decades of probably horrendously unreliable traction, but I bet still better availability than steam.

There's this belief that "standard" diesels would have been somehow better. Not notably so. USA experience with them in the 1940s-60s was up with what the UK experienced, concealed to an extent by running with common formations of four or so on a train - if one shut down it wasn't so much of an issue. The first generation, the classic streamliners (even for freight), with gangways between units, had surprisingly manual radiator shutters - it was the fireman's full time job sometimes running back and forth adjusting them, a desperate job in winter sub-zero conditions at speed, with the bodysides far more ventilated than you can imagine. The General Motors 567B engine that was turned out by the thousand at the peak of dieselisation in the early 1950s in the GP7 (road switcher) and F7 (streamliner) had a bad design water leak problem that led to the engine room being regularly awash (with a veneer of lubricating oil underneath, hazardous during such running), thus the need for big drain holes, multiple daily topups of water and periodic running out of coolant. This went on for 10 years before GM fixed it.

And that was market-leader GM. Alco classically had fuel rack problems that caused black smoke worse than a steam loco. Opinions on comparable products turned out by Baldwin for an unlucky few just duplicate BR's experience with North British.

 

[Cowley]

Never a problem on the GWR steam footplate for the previous half-century

That's why it was a whacking great bell and hooter. It would be off-topic for me to, again, give a view on the implementation of this on the BR Britannia footplate which led to the (also 1955, November) accident on the WR at Milton, you can search for that here.


There's this belief that "standard" diesels would have been somehow better. Not notably so. USA experience with them in the 1940s-60s was up with what the UK experienced, concealed to an extent by running with common formations of four or so on a train - if one shut down it wasn't so much of an issue. The first generation, the classic streamliners (even for freight), with gangways between units, had surprisingly manual radiator shutters - it was the fireman's full time job sometimes running back and forth adjusting them, a desperate job in winter sub-zero conditions at speed, with the bodysides far more ventilated than you can imagine. The General Motors 567B engine that was turned out by the thousand at the peak of dieselisation in the early 1950s in the GP7 (road switcher) and F7 (streamliner) had a bad design water leak problem that led to the engine room being regularly awash (with a veneer of lubricating oil underneath, hazardous during such running), thus the need for big drain holes, multiple daily topups of water and periodic running out of coolant. This went on for 10 years before GM fixed it.

And that was market-leader GM. Alco classically had fuel rack problems that caused black smoke worse than a steam loco. Opinions on comparable products turned out by Baldwin for an unlucky few just duplicate BR's experience with North British.

Really interesting @Taunton. The grass always seems greener.

 

[dubscottie]

What would have been the point of fitting it?
As you say, the SR weren't great users of it, while the main out-of-region running would have been on the Western Region, who used a different system anyway. Extra cost for something that had no use and was just another thing to go wrong and fail the loco.
Remember: the more safety check systems you have, the higher the probability something will fail

The 33s ran up the ECML daily to York on cement trains at the time.

 

[coppercapped]

It's a pretty terrible choice for the Abrams too, their range is awful.

The problem with gas turbines for land use is they have a very small window for efficient operation - on a ship or an aircraft, or a powerplant thats fine and theres also room to fit considerable external cooling, but obviously not much use for a car or these particular rail installations. I did wonder why no-one ever tried using four ( as an example ) turbines & igniting them in series as individual throttle notches. APT-E had four per powercar but I think they all worked in parallel? in the early days of gas turbines that might have worked out a little better, for simple reasons of experience if nothing else.

The Railway Executive should maybe have just stsndardized on some existing steam designs for urgent replacements - resisting the urge to improve things - & gone all-in on standard diesels instead - we'd have had a couple of decades of probably horrendously unreliable traction, but I bet still better availability than steam. Also by the 80s when they needed replacing perhaps we'd have been able to sustain our native capacity better...

What would they have ordered though - 1950s traffic patterns were so different to even a decade on.

It's well known that the Abrams range is limited, the choice of the gas turbine seems to have been politically motivated as Chrysler also had a diesel power plant on offer. But, hey-ho.

As both the Ivatts and the three SR diesels used the English Electric power plant I would suspect that development would have continued using this prime mover. One can postulate that by 1953/4 a production ready 2,000bhp Co-Co would have been achieved and, supported by the cash flow from increased manufacturing volumes, a 2,500bhp version two or three years later.

This raises the interesting question of whether any Sulzer powered units would have been ordered as the 1955 Modernisation Plan would probably not have needed to have been written as continuing and continuous development of the GWR's diesel railcars would have covered many secondary routes earlier. In addition the Western Region might have accepted these locomotives, as they were not quite as pre-historic and overweight as the Derby Sulzers, and as a result not ordered the hydraulics. In other words the EE Type 4 might have been a go-anywhere Co-Co...

 

[randyrippley]

It's well known that the Abrams range is limited, the choice of the gas turbine seems to have been politically motivated as Chrysler also had a diesel power plant on offer. But, hey-ho.

As both the Ivatts and the three SR diesels used the English Electric power plant I would suspect that development would have continued using this prime mover. One can postulate that by 1953/4 a production ready 2,000bhp Co-Co would have been achieved and, supported by the cash flow from increased manufacturing volumes, a 2,500bhp version two or three years later.

This raises the interesting question of whether any Sulzer powered units would have been ordered as the 1955 Modernisation Plan would probably not have needed to have been written as continuing and continuous development of the GWR's diesel railcars would have covered many secondary routes earlier. In addition the Western Region might have accepted these locomotives, as they were not quite as pre-historic and overweight as the Derby Sulzers, and as a result not ordered the hydraulics. In other words the EE Type 4 might have been a go-anywhere Co-Co...

Re the Sulzers, politics may still have resulted in them being built.
According to various tales on the internet, the UK government inveigled Vickers to set up a production line for large volumes of submarine engines during the Korean war, but then never followed that up with corresponding orders, leaving Vickers with an empty production line. The locomotive orders were -allegedly - a form of compensation for the failure to provide the military orders. Remember the dual bank engines were derived from submarine technology which allowed half an engine to be disengaged and shut down while it was serviced while at sea. How true the tale is, I've no idea.
There is another point as well - BR would obviously have wanted to fill their own erecting sheds with as much work as possible rather than using external contractors, and my understanding is EE were very loathe to allow other loco builders to use their diesels. If thats correct then it would have been unlikely for any BR built locos to use EE diesels

 

[Taunton]

There is another point as well - BR would obviously have wanted to fill their own erecting sheds with as much work as possible rather than using external contractors, and my understanding is EE were very loathe to allow other loco builders to use their diesels. If thats correct then it would have been unlikely for any BR built locos to use EE diesels

This rather passes by the huge number of Class 08s with EE engines built in BR workshops, the biggest class of all.

 

[randyrippley]

This rather passes by the huge number of Class 08s with EE engines built in BR workshops, the biggest class of all.

not particularly high-tech though compared with a mainline unit
and - I'm guessing here - that timing may have had something to do with it, Those shunter orders - or at least the bulk of them - would have been placed before EE purchased Vulcan Foundry around 1955. Until that acquisition EE wouldn't have been able to cope with larger orders as the only assembly shed they had was the Dick, Kerr tramworks at Preston. Taking over Vulcan (and by implication Stephen & Hawthorne, and what was left of Hawthorn Leslie) made them a large scale loco manufacturer - just in time for the pilot orders of the modernisation plan

 

[Irascible]

A little OT, but iirc the GWR AWS ( ATC ) worked by instantly starting a brake application which you had to cancel, so I think you'd notice even without any other warning.

Interesting about EE politics, hadn't considered that. Ignoring licensing for a minute, what other choices were there? Paxman's Ventura arrived in the mid 50s because of the modernisation plan, perhaps they could have started work a little earlier. Vickers built their own submarine engines so they at least had some home experience of developing large diesels, but Armstrong-Whitworth ( part of Vickers ) tended to go with Sulzer engines for exported rail vehicles anyway. Noone else seems to have had any larger engines - plenty of small ones, no good unless you want lots of them in one unit. Paxmans getting a big order might bave been interesting, given the Ventura is a lighter high-speed engine. The v16 would have been enough to single-engine a Type 3 - but then they'd still have to be heavy anyway because we didn't believe in braked freight!

You could, apparently, isolate individual cylinders of Vickers submarine diesels - no idea about Sulzer one.

The American experience - yes, wasn't a panacea for steam problems any means ( and I think a few US steam classes came close to the operating efficiency of even a full lashup ) but for once by *not* being pioneers we might have avoided a few issues there...

 

[Taunton]

Bear in mind the diesel contracts were with Sulzer in Switzerland, Vickers were just their preferred subcontractor for UK customers. Various pioneering or short-production Sulzer engines in BR locos were actually built in Winterthur and shipped over. Same approach applied for domestic manufacture with SNCF for the many Sulzers in France.

English Electric had a factory in Brisbane, Australia, which comparably built for that market, some full locos (which were inevitably but thus incorrectly known as "Pom's"), and some engine only supplied to railway workshops. But a lot of what went overseas was built in their Strand Road, Preston works, along with all the electrical gear for EMUs, which they didn't build themselves. It was a big place.

 

[coppercapped]

Re the Sulzers, politics may still have resulted in them being built.
According to various tales on the internet, the UK government inveigled Vickers to set up a production line for large volumes of submarine engines during the Korean war, but then never followed that up with corresponding orders, leaving Vickers with an empty production line. The locomotive orders were -allegedly - a form of compensation for the failure to provide the military orders. Remember the dual bank engines were derived from submarine technology which allowed half an engine to be disengaged and shut down while it was serviced while at sea. How true the tale is, I've no idea.
There is another point as well - BR would obviously have wanted to fill their own erecting sheds with as much work as possible rather than using external contractors, and my understanding is EE were very loathe to allow other loco builders to use their diesels. If thats correct then it would have been unlikely for any BR built locos to use EE diesels

I would suggest that the various tales on the internet are just that - tales.

Sulzer developed the LD engine specifically for rail use with no compromises for industrial or marine use. For example it used a very rigid crankcase to avoid flexing problems which had occurred on earlier diesels used for rail traction but which was overkill for industrial and marine applications. Factories tended to have rigid floors and although ships flex the length of the bit under an engine is effectively rigid. The first LD was built in, IIRC, 1934 and the twin bank engine also dates from before the Second World War being used in locomotives in France and Romania. As far as I know no submarine ever used the LDA engine - the Americans used Fairbanks-Morse, the Germans used MAN engines (one of which ended up on the top of the Nebelhorn mountain in Germany after the war powering a cable car!) and the UK used Paxman.

Sulzer engines were built by many companies and in the UK Armstrong-Whitworth built some between the wars. Armstrong-Whitworth merged with Vickers in 1927 to become Vickers-Armstrong which is why BR's Sulzer engines were built by Vickers. I know of no Korean War submarine linkage.

 

[Irascible]

The T-class subs ( admittedly a pre-war design ) used Vickers own design, Admiralty, Sulzer & even MAN engines ( I bet those were fun when the war kicked off ); everything non-experimental after that was as you say Paxman or Admiralty. The only diesel fast naval craft we ever had used Deltics ( for some reason we preferred petrol ) so no clues for possible designs there either. I could imagine Paxman's clean sheet which became the Ventura being started earlier & them getting a fair market share, but could they have built enough engines to keep up with whatever EE wasn't going to build? mind you one could also see EE just buying Ruston & Hornsby early & blocking that...

 

[randyrippley]

I'm not convinced that Paxman would have been significant -every UK rail application for their diesels prior to the Valenta seems to have been doomed to failure.
Class 15,16,17,27 and the one-off Warship, none took the market by storm. They only got things right with the Valenta in the HST. I suspect an earlier expansion using the early Ventura designs would have been a technical failure and put the company at risk.

Did they ever supply a DMU engine in the UK? I read somewhere that the engines in the Claytons were originally intended for railcar underfllor use.