DHP1

I came across some info on line yesterday about this prototype diesel loco and I had never heard of it before. It looked a bit like the class 17 Clayton locos, but was bigger and it, apparently, had four Rolls Royce engines and hydraulic transmission.

It appeared to be a demonstration loco, like D0260 and D0280, but seemed to be very obscure and little known. Does anyone know any more about it? Where did it run?

 

Some info here:

https://en.wikipedia.org/wiki/British_Rail_DHP1

 

I think this was the loco with 4 engines that chopped in at different speeds/power demands. There was an interactive display at the NRM York (in the warehouse section) demonstrating how this worked for many years, don't know if it's still there?

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A photo of DHP1 can be viewed here: http://www.railphotoarchive.org/PhotoViewerV5.php?img=0146020007000

 

I think your thinking of the Fell Diesel
DHP1 was known as the ‘Super Clayton’
2 rather interesting images are on Class47.co.uk of it sharing space with the Cuban class 47s under construction at their works in Derby

 

I think there was an article on the beast in Railway Mag not too far back with some photo's and it's (unsuccessful) exploits out from Derby up toward Buxton if (failing) memory serves.

 

You can buy a model of it now:

https://krmodels.net/product/clayton-dhp1/

 

Mark Alden did extensive research into DHP1 and published a major item on it in one of the mags maybe 15-20 years ago but i can't recall which mag it was.

ITYF almost all the gen found anywhere else is drawn from that item, be it on wikidribble or any other mag that has run something on it since. Somewhere buried in my boxes are the pages from Mark's article, but I not the time to go mining for it.

DHP1 had, by all reports, 4 x RR C engines; somewhere I have seen some speculative but informed comment that the 4 off RR DV8T engines used on Claytons D8586/87 had some connection with the DHP1 project, possibly bought in advance as alternatives for more power then diverted to replace written off Paxman 6ZHXLs. Who knows, it was a good theory anyway.

It is far from clear what on earth DHP1 was built for, even as a demonstrator it would not have been of much interest to BR, and was certainly a truly "non compliant bid" if they were after offering it in the then BR Standard Type 2 tender competition.

But it was very light weight; 1500 hp in 14 ton axle load. BR still had very low axleload lines at that time, so that is what it might have been after.

There was another almost unheard of, but earlier lightweight prototype also from Clayton - the BTH / Clayton Explorer; a sort of enlarged D8200 but CoCo, 50% more powerful, with a Lister Blackstone engine, and very light axle load, with bogies designed for metre and colonial gauges as well as standard.

Explorer always gets put down as being for export only, as that is where it ended up, having never run on BR to any certain knowledge and it's multi gauge feature; nonetheless it was sure to have been run by and or inspected BR at the time, if only in works - as it was 1200 hp from only 12 ton axle load, and as above, BR /then/ had some lines needing such a light axle load they had no suitable diesel for except shunters.

One link to it is here
https://www.derbysulzers.com/AEI.html
scroll down a bit

There is some more gen on it
https://rogerfarnworth.com/2018/06/...and-rolling-stock-part-d-diesel-1948-to-1977/
although I suggest some of the wording is a little vague and makes assumptions.
It was still about, preserved, or destined to be, mid 2000s; no idea of it since.

The other point of interest with Explorer is often - but incorrectly - stated that the Sulzer 12LDA engine in 44/45/46/47 was unique in rail traction as a double bank in line engine; the Lister Blackstone engine in Explorer was exactly the same configuration, a double bank in line 12.

 

IIRC the role for DHP1 was as a contender for the Type 3 specification which resulted in orders for the Classes 33 / 35 / 37 but the problems with the Clayton Class 17 and the associated costs of rectification left Clayton out of the running. In retrospect it is interesting that the third batch built by Beyer Peacock (D8588 - 8616) proved better survivors once transferred to Scotland and suggests that any problems that arose were due to the Paxman engine and not the design of the loco per se. It would be interesting to hear from the DTG team about their experiences with D8568 which seems to be a more reliable workhorse under their care.

 

The suggestion in the first link is that Explorer was scrapped in 2011.

 

No way Fred.

DHP1 dated 1962.

Every 33 and 35 ever built was already on order by then if not actually in service, as was every 37 of the first group (ie the initial specified "split box" for want of another demarcation point).

Apart from that, DHP1 was a lightweight : 56 ton total (14 ton axle load) opposite of mainstream needs for tractive effort and braking power (a function of weight).

Even the Western Region with its pro hydraulic + all axles powered + lighter machinery policy would never have gone to that extreme vice Hymek for a mixed traffic Type 3.

If they were a contender for the second 37 group, how useful, assuming they worked, do you think 2 or 3 x DHP1 would have been on Port Talbot - Llanwern or Tyne - Consett ore trains ? Or slogging up to Ebbw Vale with 1000 tons on its ownio (well slogging is hardly an appropriate term there). Or even braking the empties coming back ?

 

Don't think I agree with you assessment given that orders were place for Class 37s for South Wales from July 1962 onwards. IIRC the GWR wanted to eliminate steam from South Wales and ordered Class 37s to achieve this - D6819 - 6918 in July 1962; D6919 - 6938 in 01/64; 6939 - 6999/6600-6608 in 02/64 hence there was a narrow window available for a Type 3 design to achieve this. Whilst I have no written records to confirm the facts the suggestion that the GWR may have been interested arises from the fact that its internal structure was compatible with both the GWR Classes 35 and 42 diesel hydraulic classes.

This information is covered in an article on the locomotive published in the October 1998 edition of the Railway Magazine which notes the the primary purpose of the locomotive was as a testbed to put into practice the ambition of Rolls Royce and Clayton to provide a four-engined power plant, torque converter and gearbox arrangement allied to the concept outlined by Lieutenant Colonel Fell and tried in his test locomotive 10100. It appears the intention was to provide a powerful locomotive with low axle-load of 14 tons suitable for export markets. As far as Britain was concerned it had 2 major failings; (1) the diesel electric had proved its superiority and any other drive chain was given little credence and (2) Rolls Royce abandoned work on the gearbox in October 1963 and withdrew from the project hence further development was slowed to a virtual stop.

Based on the article in Railway Magazine it appears that DHP1 ended up as a "What if" project that failed because it was produced at the wrong time for the market that it might have served but which was ultimately better served by the Class 37s even though evidence was available to show that the Class 35 fleet was proving to be the equal of a Class 37 fleet albeit with the much detested hydraulic transmission hence the latter's demise.

 

Not sure what you are saying there Fred.

The BP built batch had the same Paxman ZH engine as the Clayton built batch - but your wording seems to me to imply you think otherwise.

The root cause of the early, in some cases catastrophic, engine failures was torsional vibration along the engine crankshaft caused by poor mis match with the GEC main generators.

The 6ZHXL was very extensively tested by BR under that DEMU
https://www.railcar.co.uk/type/paxman/
although a flat engine designed for underfloor dmu use, it was passed by BR, the two engines ran 43000 miles sucessfully then adopted in the D8500 design. If you think about it, there are not that many engines BR used, EE 16SVT excepted, that got that amount of trialling before en masse orders were placed.

But.

In that DEMU the ZHs drove BTH man generators. The Clayton batch of D8500s had GEC main generators - so was a new untested set up. This combination resulted in torsional vibrations. It is the sort of thing these days easily overcome at design stage by computer analysis way before anyone starts cutting metal but near impossible to predict then. It is also very easy to fix, you just fit different engine vibration dampers,or other damping.

The vibration problem was so severe it literally wrote off several engines within weeks of leaving works. This that were not destroyed were modified, but were permanently damaged w.r.t. their fatigue life. Hence they were always trouble. There were about 40 completed D8500s, so some 80 engines, in total affected; the higher numbered Clayton build got modified engines from new; D8568 was one of these BUT that is not to say power units were not swapped around, they almost certainly were.

The BP batch of D8500s had CP main generators and the issue never arose in th first place. But it was the same engine.

None of that is a problem with the ZH engine per se, the problem was matching. It could equally have happened the other way around i.e. with CP and not GEC, or not at all, or with both, or with any of the other AEI or EE equipped D8500s that were tendered for but never ordered.

It is true the Paxman ZH (and the YH in D8200 D8400) were not brilliant in terms of aluminium components, but that issue is nothing to do with the early vibration trouble, and would have been easily fully addressed had BR chose to do so; but by then the D8500s were already on their way out what with traffic cuts and freight demand falling etc. The gamut of mods that were implemented is in the Class 17 history book the full title of which is upstairs and i can't be bothered to go look.

Minor point, the BP batch is not the "third" batch. They are the second batch; the Rolls Royce engined D8586/87 were always part of the first batch. Three sub classes yes, three batches no.

 

Not sure what you are saying there Fred.

The BP built batch had the same Paxman ZH engine as the Clayton built batch - but your wording seems to me to imply you think otherwise.

The root cause of the early, in some cases catastrophic, engine failures was torsional vibration along the engine crankshaft caused by poor mis match with the GEC main generators.

The 6ZHXL was very extensively tested by BR under that DEMU
https://www.railcar.co.uk/type/paxman/
although a flat engine designed for underfloor dmu use, it was passed by BR, the two engines ran 43000 miles sucessfully then adopted in the D8500 design. If you think about it, there are not that many engines BR used, EE 16SVT excepted, that got that amount of trialling before en masse orders were placed.

But.

In that DEMU the ZHs drove BTH man generators. The Clayton batch of D8500s had GEC main generators - so was a new untested set up. This combination resulted in torsional vibrations. It is the sort of thing these days easily overcome at design stage by computer analysis way before anyone starts cutting metal but near impossible to predict then. It is also very easy to fix, you just fit different engine vibration dampers, or other damping.

The vibration problem was so severe it literally wrote off several engines within weeks of leaving works. Those that were not destroyed were modified, but were permanently damaged w.r.t. their now reduced fatigue life. Hence they were always trouble. There were about 40 completed D8500s, so some 80 engines, in total affected; the higher numbered Clayton build, 45 or so, 90 engines, got modified engines from new; D8568 was one of these BUT that is not to say power units were not swapped around, they almost certainly were.

The BP batch of D8500s had CP main generators and the issue never arose in the first place. But it was the same engine.

None of that is a problem with the ZH engine per se, the problem was matching. It could equally have happened the other way around i.e. with CP and not GEC, or not at all, or with both, or with any of the other AEI or EE equipped D8500s that were tendered for but never ordered.

It is true the Paxman ZH (and the YH in D8200 D8400) were not brilliant in terms of aluminium components, but that issue is nothing to do with the early vibration trouble, and would have been easily fully addressed had BR chose to do so; but by then the D8500s were already on their way out what with traffic cuts and freight demand falling etc. The gamut of mods that were implemented is in the Class 17 history book the full title of which is upstairs buried in boxes and I can't be bothered to go look.

Minor point, the BP batch is not the "third" batch. They are the second batch; the Rolls Royce engined D8586/87 were always part of the first batch. Three sub classes yes, three batches no.

 

I did not go into dates with the WR 37s, but, if what you say is right, ordered mid 1962, then the WR 37s also align with being placed before DHP1 was ready as the Type 3 tenders would have been issued at least 6 month before (and the spec was off top of my head mid 1960). So you are actually providing evidence agreeing that DHP1 was not a contender, it was about 2 years too late.

 

Thanks for all the interesting posts and info guys

 

I rather like the look of that DMU you linked to, even though it's a "bitsa".

 

Thanks to D7666 for the exposition of the development stages of the Paxman engine which adds to the knowledge of adopting marine engines for rail traction purposes - as Paxman engines were originally applied to. Paxman seems to have proved troublesome in many ways as Richard Hardy was less than complimentary about the Class 15 and 16 examples when allocated to Stratford. When the Class 14s arrived at Corby - replete with alloy heads - the Minerals Department quickly solved the coolant problems by fitting cast iron heads - a solution applied to the HST power cars shortly after their introduction to service IIRC. I was also advised by the team leader who restored D9531 to service that many of the improvements he had made were many that would have been adopted by BR had they retained them for service - subject to the financial constraints that were applied by various bodies (e.g. accountants, Treasury)

I note your comments on the "batches" but my definition of batch is not by order but by specification hence the pair of Rolls Royce - fitted locomotives I consider a different batch from the "standard" locos fitted with Paxman engines and GEC electrical equipment. A minor difference of interpretation perhaps but proves one needs to be talking about the same things when discussing matters - I acknowledge the differences in interpretation given your greater knowledge of the engineering side as my interest is more in the operating side.

 

it never ran in service, only trials.

 

Shame. I've just finished reading a photo-album by Transport Treasury on first-generation DMUs and have one or two other books that cover the early diesel railcars in more detail. The pre-war streamlined LMS one looked rather special.