Double chimneys.

When you have made a huge financial commitment to a system, a way of doing things, and this system has grown over a number of years it becomes very difficult to change it significantly. The very notion of having to re-train artisan shed staff to deal with a significantly improved locomotive design was enough of a reason to make people think twice.

The very size of the system makes it rather less agile when it comes to dealing with the impact of external forces. Also, when you have been successful and profitable for many years, when you have had a near monopoly in an area of the market, it is too easy to become complacent.

Modifications. Some reactions to this word are rather telling. Elsewhere in the world when it has been found that a significant class of locomotives is incapable of meeting the requirements of the traffic department (or of the passengers) the class has had a number of aspects attended to. Far cheaper than building new locomotives. Strengthen the frames, fit an optimised exhaust system, refine the steam circuit and the job was done. No "fancy improvements" just a touch of superior engineering. Not all sweetness and light though. The improved engines were more powerful, they were more efficient too in that they required much less coal per dbhp hr. They could keep time, regain lost time, replace far larger machines on other duties if the need arose. The accountants had a problem in that they cost more to run. Maintenance? No. The fuel bill. The revised engines used far less fuel for a given amount of work. The trouble was that they had the power output to do so much more than they had originally been capable of. And the crews used that power. Trains ran to time. Traffic and passengers were happy.

And this takes us back to double chimneys. You get better steaming, improved efficiency, higher maximum power output. But if you want more power you need to burn more fuel and the point is reached where your modified machine is costing you more to run.

 

We've been here before but SNCF - the home of some fairly advanced locos - kept simple, two cylinder locos to see out steam on the network. There must have been very good reasons why the more complex designs were withdrawn earlier. Compounding found favour on the individual state railways of Germany but fell out of favour when the Einheitsloks began to appear and again simple, mostly two cylinder locos saw out steam on both sides of the Innerlandgrenze. This story is repeated many times over so are we saying that all of these countries had over conservative views on loco development?

 

Remember that they both have the benefit of a larger loading gauge, therefore larger cylinders can be used.

 

Don Ashton's site is back up again.

http://www.donashton.co.uk/

The individual pages titled Walschaerts, Stephensons and More Cylinders all seem to have material germane to the discussion. I'm afraid I just don't understand the basics sufficiently to understand everything he is talking about, but he states that there were advantages to the inside Walschaerts on the Kings and Castles as far as locating components are concerned. Amongst British design schools he seems to rate the GWR and LNER teams best (and Beyer Peacock), with an honourable mention for Bulleid/(Jarvis?), but a rather lower opinion of the LMS/BR design team.

I think its fairly clear that, rightly or wrongly, the GWR put a rather higher priority on even valve events than other lines: indeed Cook says as much in his book "GW locomotives had extreme regularity in their exhaust beats and we certainly could not permit of anything like two beats and a woofle which was noticeable on some other lines"

I've also just found a Holcroft quote in "the Engineer" in an article on conjugated gears - http://www.gracesguide.co.uk/images/d/de/Er19460215.pdf p145.

"In the case of the steam locomotive it is characteristic that practical considerations have always prevailed over those which may be held to be more desirable on theoretical grounds, and utmost simplicity is sought for reasons connected with operation in traffic, maintenance in running, general repairs, and low capital cost. Saving in fuel and water consumption is important, but it must not be obtained at the expense of these other items. Simplicity also contributes towards reliability. "

 

Yes, re. the SNCF we have been here before. Taking the 141R design. This was at a very significant mechanical advantage no doubt about that. French drawing office practice was a real problem. If you take trip to Mulhouse compare and contrast American and French design. In terms of locomotive design there is little excuse for not adopting the best, both from the mechanical and the thermodynamic fields. The locomotive builders in the States were very good, by and large, with mechanical design. They had to be given the distances to be worked and the utilization patterns.They were less good at the thermodynamics. You want the proof, check the power to weight ratios. In France through the efforts of du Bousquet, Chapelon, de Caso and others pushed the thermodynamic aspect of design but mechanically they had a problem and Chapelon knew it. Back to the R and, say, a 241P. The French locomotive has wedges and bolts for on shed adjustment not quite everywhere but pretty close. All demanding inspection and attention. Not something that you want unless you have a large quantity of skilled, cheap labour and a significant amount of time. With the R you do not have this problem.

From the point of view of the shed master in a post war world you need the convenience offered by good mechanical design. An accountant with a close eye on the fuel bill may have other ideas.

Ideally you want the power and efficiency of the compound coupled with the best in mechanical design. This was recognised and the designs produced. Sadly none were built. The compound was very little more complex than an ordinary simple expansion engine. The intellectual complexity was another matter.

On valve gear, some companies deliberately had a distortion built in to allow the piston thrusts to be equalised with reference to the effect of the piston rod. For some this equality was more important than an even exhaust beat.

 

From what I've read, compound Mallets fell out of favour with US railroads due to them being slow and plodding. There were exceptions if course - the N&W and C&O persisting with the type until the end of steam but most of the bug articulated designs were simples. I wonder the reason for this. There were was a lot of cheap coal available so perhaps the economics were such that the added complexity outweighed any savings.

 

232 U1 must come very close to this ideal with its American inspired roller bearings, Franklin wedges and mechanical stoker, coupled with only two sets of valve gear for four compounded cylinders. A production series very nearly materialised but the very same shortage of indigenous energy in pre-nuclear France which had led to the attention given to thermal efficiency led also to an early cessation of steam development. The glow-worm strength of light bulbs and restricted periods of street lighting (as recounted to me by an elderly relative) in pre-war France were for valid, if regrettable, economic reasons.

This particular locomotive impresses me far more than anything which ran in GB but it must have been very expensive to make. To a mentality which seemingly sought to remove the Kylchap exhausts from the A4s so fitted it would have been quite incomprehensible no matter its performance or economy!

P.H.

 

Very interesting site, thank you for posting that link. The comparison of the LNER B1, GWR Hall and LMS Black Five was food for thought. All very similar machines in terms of tractive effort, size and layout but the differences in valve gear and other details are apparent.

 

The French have, shall we say, a peculiar attitude to their heritage. 232U1 though not quite reaching the performance and economy standards of Chapelon's designs is a truly magnificent machine. In any other country............
It is and was fully developed for series production. I agree with you P.H. de Caso's last Baltic would not have been cheap. But show me a high power locomotive that is! The better the locomotive you design, the fewer of them that you need. The N & W did not need many of the Class J.
You can of course limit your building program to small, cheap locomotives. The downside is "Midland Syndrome". Particularly after the influence of Granet.

Compounds end up being "slow and plodding" for largely the same reasons that simples do. A badly thought out steam circuit is just that regardless of type. Intellectual challenge and all that.

 

The fact is, the steam engine was capable of considerable further development, and the knowledge to make those developments existed in the 1950's and could have been used to get a better return on capital than mass dieselisation. Eventually - by now, for sure, the steam engine would have been replaced. But BR in particular wasted a huge amount of money on largely indifferent designs, both steam and diesel, while at the same time rushing into many other changes which damaged their business. It's no good saving money by replacing locos and track if your freight wagons then start derailing because they are still basically an early Victorian design.

Altogether, its a sorry tale. And some of that blinkered thinking is still around.

 

I dunno. Could the workforce to maintain a large steam fleet have been maintained into the 1970s do you think? Those kinds of job - low paid and filthy - were a lot less than popular. And all the clean air acts and so on would have had an influence too. There's not much doubt that the whole sorry affair was botched, and maybe we'd still have a rail building industry if the introduction of new locomotives hadn't been such a stuff up, but if mass dieselisation had been postponed more than a few years I'm sure another set of big problems would have come over the horizon. Truth is the diesel engine as a motive power technology had come of age after the war, and even if steam power could have been improved from hideously inefficient to merely grossly inefficient it wouldn't have been enough. I'll agree though that the way things happened was pretty appalling.

 

[QUOTE="242A1, post: 848321, member: 980"You don't haul trains without horsepower. If you need it there are only so many variables you can juggle with. You can only take boiler pressure so far on a traditional water leg firebox. Metallurgy limits your degree of superheat. Loading gauge limits cylinder size. The 504 rule dictates driving wheel diameter. Then, if as a designer, you wish to minimise the peak over mean tractive effort difference you go multi cylinder and compound if you know how to make it work. The BR board seriously underestimated the power that would be needed which explains why the East Coast received 3300hp diesel electrics. Strange to say this figure was easy to surpass with steam. Trouble is the people that understood this did not work in the UK.[/QUOTE]

Sorry, but what is the 504 rule?

Dave

 

The steam locomotive was and indeed is capable of a very significant amount of further development. You not only develop the thermodynamic aspect but also the mechanical. Note that a locomotive type that uses one fifth of the fuel that its alternative uses is under severe pressure if the fuel it uses costs ten times as much per unit as the fuel type used by that alternative locomotive type. Then you have the capital cost, service life, maintenance costs etc. Generally when all factors are taken into consideration steam is at no particular disadvantage. Politics and back handers can work wonderful things, so the analysis tends to be at best ignored.

Access to an instantaneous exhaust gas analyser reveals just how misplaced the concept of the steam locomotive having particularly dirty emissions is. So the environmental case does not hold too much water either.

When the EE class 5 was introduced at 3300 hp steam should have already been achieving 4000 hp given the level of understanding that existed from the 1930s and 40s. So what didn't UK designers understand and more importantly why?

Working conditions did not need to be poor. The Norfolk and Western had white tiled lubritorium bays. Have a look at Shaffer's Crossing and then the date when it was developed. Then look at the UK shed facilities. Improved locomotives require less shed time and hence fewer shed staff. Better facilities allow for faster turn arounds, fewer locomotives and again fewer staff.

I have argued long enough that UK steam locomotive designers were not of the first rank, certainly not after WW2. There may have been mitigating circumstances but at the end of the day they can only be judged as second rate.

504 rule from the AAR, maximum rpm of driving wheels.

 

one of the biggest problems was shortage of coal in the late 1940's and 1950's. this was a BIG political problem when several severe winters were experienced. Voters didnt like having no heat in their homes! one of the easy solutions was to phase out UK steam. then North Sea gas came along a few years after this policy had been implemented to it's conclusion.

cheers,
julian

 

Could Steam have been maintained into the 1970's? I think it could.

First, you'd go ahead with converting all shunting to diesels, that technology was proven.

Second, you'd concentrate your steam on 'out-of-town' sheds and longer distance freight work which could be served by sheds like March where the work was still wanted, dirty or not. City end sheds would be redeveloped exclusively for diesels - or, if you like, Chapelon / N+W inspired steam. Both would require more training and would be better quality jobs which the people working on traditional steam could aspire to and which would be more appealing to potential employees in the city areas with their wider choice of careers.

Third, you'd continue the DMU revolution and suburban electrification. Slow stop-start stuff is not the best use of steam. Traditional steam would be gradually reduced to long distance secondary passenger and line-haul freight - the things our most modern steam locos in existence in the 60's were suited for - until finally phased out sometime in the 90's.

In the meantime you'd have replaced the appalling Victorian goods wagon with modern bogie stock using airline style containerisation and mechanised handling, even at wayside stations, to retain the wagon-load freight that was totally lost. You'd do that using the money you hadn't spent on overweight unreliable 'modernisation plan' diesels, among other things. The Freightliner network was one of the good things that came out of the 'modernisation' era, but it didn't go far enough in catering for smaller loads and local pickups and destinations - once you've put something on a full-size long distance lorry its likely to go all the way on said lorry. Nor did it really do anything for block loads, although there we did eventually modernise the rolling stock - again much later than it should have been, but at least in time to retain some of the traffic.

Why on earth should there have been a shortage of coal? There are thousands of years worth of the stuff under Great Britain.

 

I believe the good stuff was sold abroad to get hold of hard currency. WWII and the aftermath did almost bankrupt the UK.