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jools1959

Questions about the North British Class 41 D6xx Loco's

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There seems to be very little in the way information about these diesels when they were in service apart from the fact they were overweight and quickly replaced by classes 42 and 43.  Given the fact that they were non standard by being small in class and BR's diesel hydraulic policy, did they give good value for money or were they plagued with problems which we read about, like the classes 15,16, 17, 23 and 28?

 

From what I can gather, they were good "pullers" and rode well, and lot of information was gleaned from them when the class 52 Westerns were being designed but, again because they were small in number, they were concentrated at LA because of traction knowledge and a ever decreasing shortage of spares, though in the late 60's, some or all of them were transfered to South Wales, so BR must have had some faith in them given the fact the valleys were swarming with class 37's.

 

Given the fact they lasted about 10 years, that's about average for most of the pilot scheme loco's, were they a hit or a miss?

 

Julian Sprott

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An enormous great miss - desperately unreliable (although some of that was down to the boilers), overweight in a way which completely destroyed the whole idea of having an hydraulic transmission, atrocious build standards, an engines which were notorious oil-throwers.  I think that in many respects apart from being able to be made available earlier than the Swindon design they were as much a political sop to both the BTC and to order a Type 4 diesel from North British as they were a practical contribution to the Pilot Scheme although they did provide a testbed for the MAN engine and one design of (Licence built) Voith transmission.

 

They did have the advantage of adhesive weight but even with that their maximum permitted loads on passenger and milk etc trains were less than those of D8XX.  I think that far too soon it was simply a case of keeping them somewhere handy to a depot which could repair them and not wasting money on training too many men how to drive them.  I suspect the only reason that they survived as long as they did was because of the embarassment which would have come from scrapping them any earlier.

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IIRC The engines and transmissions in at least some of the D600s were german built as NBL hadn't got their licenced production line set up.

 

2 things are very telling though - the Germans tried 3 engine types in their V200s - MAN, Maybachs and Mercedes - and guess which one they dropped like a hot potato! Also when the Germans visited the UK they were horrified at what we were asking of our hydraulics - 14 on, 80mph - have a look at pictures of V200s, generally much lighter trains.

 

Mike's summation hits the spots for the D600s - unwanted children of the BTC - but the D800s, even the MAN engine ones - were capable of prodigious feats and reliability was at least as high as contemporary diesel electrics

 

Phil

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There sometimes seems to be an almost inverse relationship between the success of locos on the 1:1 scale railway and their following among enthusiasts. We find the "failures" such as D600s and Claytons somehow more interesting.

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Depending on how the reliability figures are worked out, the Swindon built D800s were turning out better availability figures than the Type 4 diesel electrics in service in the 1960s.

We (I) have been here before on the question of availability figures and it all depends how they are measured and as different regions used different methods that can distort the results.  The Western measured availability against total fleet of any particular type - e.g. you have, say, 100 locos and if 75 of them area available for traffic you have 75% availability - the other 25% might be in works, undergoing a big (several days) exam, or a failure and not available for traffic.  Some other Regions measured availability by starting with the number of locos which were not in works but were actually working (in theory) and in some cases even those undergoing a big exam were not counted.  Thus your class of 100 might immediately reduce to, say, 90 and thus if 75 of those were actually available you had a better than 75% availability.

 

Another interesting thing was the big final exercise of comparing diesel hydraulic and diesel electric maintenance costs.  At that time only one depot on BR had, for maintenance, a mixed fleet of Type 4 diesel hydraulics yet rather oddly the figures for comparative purposes were taken from two different depots instead of using those from Canton.  It was suggested by some folk on the WR at the time that the main reason for that was that at Canton the maintenance costs for D10XX were lower than for its Brush Type 4s. 

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Yes indeed - and with the D800s Swindon hand built the first loco, translating the german metrics in to imperial - and then used the jigs for the rest of the class. It was largely the NBL built components that hobbled the hydraulics but despite that the concept was right - wasn't it?

 

Phil

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Even on their initial delivery run before acceptance by the W.R., problems with loss of oil. According to an ex-fireman of Wellington (Salop) D600 was incarcerated at Wellington after just a few miles on the W.R. No W.R. staff in the area had any experience of mainline diesels let alone the N.B.L. products so had to wait for " technicians from Scotland ". Apparently, the W.R. hierarchy were non too pleased and instructed Wellington staff not to mention the incident.

IIRC, in later years, the concentration at Laira was partly due to their mastery of the Cornwall line when behaving. I believe the idea for Pantyffynon/Llandeilo area coal trains was because of their pulling power but after a few trials were deemed unsuitable and nowhere else wanted them so they were consigned to scrap.

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You do wonder if diesel-hydraulics would have a far better reputation had North British never been involved. Don't forget their diesel-electrics were just as bad, and shorter-lived than their hydraulics.

 

David Clough's Hydraulic vs. Electric – The Battle for the BR Diesel Fleet claims that the better hydraulics, particularly the Hymeks, were at least as reliable as the majority of contemporary diesel-electric designs.

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There is still a lot of kit in use that uses hydraulic transmission. Not just on the railways but on farms, building sites, etc. If well manufactured, every reason why, in the long-term, it should be more reliable than electric. And surprisingly easy to maintain. Remember snow (the wrong kind) getting into 317 traction motors.

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The small numbers in the hydraulic fleet told against it. Standardisation was the name of the game. You have to look at through life costs, and small fleet sizes do not help. The power to weight argument was changing. DE units were becoming lighter for given power outputs. This has carried on. Look at today's modern kit and that trend is continuing. Besides, modern computer control must be easier to interface to DE traction?

 

Don't forget that the majority of diesel passenger traction in Britain has hydraulic transmission - all the 15x, 16x, 17x and 18x DMUs.

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I can appreciate BR's dilemma. Initially, when the hydraulics were ordered, the goal was to eliminate steam as fast as possible and try to portray a modern mode of transport fit for the coming 'space age', together with the way motorways were being viewed. The WR had made a case for lightweight diesel locos which must have looked tempting when compared to the lumbering giants that were the EE Type 4s and the Peaks.

 

With Beeching cuts and steam eliminated, the organisation had done all that in 10 years or so, but BR were still only just about managing to break even for a year or two; so other efficiencies had to be found, and all non-standard stuff had to go in favour of loco types built in large quantity which (after training of staff) could be serviced anywhere on the system.

 

Sadly, I only ever saw D603 in service, at Penzance when on holiday in 1963.

 

I remember reading a report in a Railway Observer from about 1958 that BR had given the preliminary go-ahead for another 30 of the class at that time, although certain reports in RO have to be taken with a large pinch of salt. However, there may have been a time (albeit extremely short) when the D600s were seen as the locos of the future.

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I remember reading a report in a Railway Observer from about 1958 that BR had given the preliminary go-ahead for another 30 of the class at that time, although certain reports in RO have to be taken with a large pinch of salt. However, there may have been a time (albeit extremely short) when the D600s were seen as the locos of the future.

 

Can't remember the source either, but I've read that too. The order was cancelled in favour of what became the 43s, which used the MAN engines and transmissions already on order.

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I remember reading a report in a Railway Observer from about 1958 that BR had given the preliminary go-ahead for another 30 of the class at that time, although certain reports in RO have to be taken with a large pinch of salt. However, there may have been a time (albeit extremely short) when the D600s were seen as the locos of the future.

Didn't NBL get the order for class 43s as compensation for losing out on the D600 production order?

Edited by pete_mcfarlane
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Don't forget that the majority of diesel passenger traction in Britain has hydraulic transmission - all the 15x, 16x, 17x and 18x DMUs.

Not all 17x though - 172s are diesel-mechanical (and the worse for it! - yes I know the argument about fuel-savings!).

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Those are all DMUs with distributed power sources and drives. If you look at heavy haul locomotives, i.e. classes 66, 67, 68 and 70, that is DE with a single large power unit and increasingly sophisticated control to the traction motors.

Isnt that because you need all the gubbins as protection for the electrical systems?

 

Phil

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When NBL was in financial trouble there was pressure on the BRB to give NBL an order for a type4 co-co design it had with a 12LDA sulzer engine. I wonder how these would have performed and how long they would have lasted

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There sometimes seems to be an almost inverse relationship between the success of locos on the 1:1 scale railway and their following among enthusiasts. We find the "failures" such as D600s and Claytons somehow more interesting.

 

I still think that the D600s  were the most handsome of all the early diesels.

 

Keith.

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When NBL was in financial trouble there was pressure on the BRB to give NBL an order for a type4 co-co design it had with a 12LDA sulzer engine. I wonder how these would have performed and how long they would have lasted

 

About as long as their diesel-electric version of the 22, at a guess.

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I don't see the logic in that reply.

 

The 21s did not have Sulzer engine, and from what I have read it was their MAN derived engine that gave the most trouble.

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It was not just BR that experimented with hydraulic drive, in the 1958, the US, Southern Pacific and Denver, Rio Grande and Western ordered three Krauss=Maffei ML4000 4000hp C-C loco's each and evaluated them on some of their demanding routes.  DRGW quickly gave up and sold their three on to the SP.

 

SP were suitably impressed with theirs but only in the largely flat areas of the bay area and central valley and nicknames "flatlanders".  In the early sixties, SP went back for 15 more M-K's but with detail differences.  SP also ordered three huge ALCo DH643 home built loco's for evaluation using German technology but by 1967/68, the experiment was over and M-K's all bar one were scrapped.  The ALCo's lasted a little longer and were gone by 1971/72.  Non survived.

 

Their small build, fragile nature, different technology and metric tooling, and the biggest killer was the exchange rate.  Like the NBL class 41's needing to be based at LA, the M-K's and ALCo's had to based at Roseville near Sacramento.  They were often MU'ed with diesel electric loco's often as insurance.

 

I think the only successful railway to use DH technology was Germany's DB.  Mainly because all the resources were nearby.

 

Julian Sprott

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I don't see the logic in that reply.

 

The 21s did not have Sulzer engine, and from what I have read it was their MAN derived engine that gave the most trouble.

Agreed - the Paxman re-engine 29s were much more reliable.

 

Neither should it be forgotten that for 10 years the WR of BR relied significantly on hydraulics - diesel electrics were not that common west of Bristol until the early 70s

 

Phil

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David Clough's Hydraulic vs. Electric – The Battle for the BR Diesel Fleet claims that the better hydraulics, particularly the Hymeks, were at least as reliable as the majority of contemporary diesel-electric designs.

A strange book this. Interesting in some ways, but rather too many unsubstantiated statements to support his previously held views. Let's just say he's not much of a DH fan, and the lack of balance makes for an irritating read.
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You might conclude that the hydraulics were largely sorted - or perhaps understood! - by the mid 60s. It was politics in the BR engineering hierarchy and perhaps a desire in senior management to repress the independence of the "Great Western Region" that did for them!

 

If anyone hasn't seen it have a look at Downendian's current thread for superb pictures and further discussions

 

http://www.rmweb.co.uk/community/index.php?/topic/95191-neils-hydraulic-pics/

 

Phil

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I think the only successful railway to use DH technology was Germany's DB.  Mainly because all the resources were nearby.

I always thought this was because of restrictions put on the Germans immediately after the war, to stop them developing diesel-electric generator sets which could also be used in submarines. So they didn't have much choice but to make hydraulic transmission work. 

 

IIRC correctly there was a period of a few years after the war when the Germans were still regarded as a defeated enemy and not to be trusted, before it was realised that the West Germans might be quite useful in a fight against the Russians. 

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