Crimson Rambler

Train set looking good David Ah Bedford for the coaling stage - you know it makes sense to relocate the whole layout further south! Will ring in the week, re cigars and a chat. Crimson Rambler

I believe that many of the South Wales coal wagons used in the export trade that had sprung buffers one end and dumb the other (1860s, 1870s) had the couplings arranged so that they would only readily couple sprung end to dumb end. Crimson Rambler

To clarify John-Miles observations, by steam circuit, I meant the pathway taken by the steam from the boiler water/steam interface to the point where it enters the cylinder and then from where it leaves the cylinder until it has escaped from the blast-pipe. Perhaps it’s not a good choice of word but my defence is that Chapelon used it and he was quite a good locomotive engineer! Thus, from this definition the regulator is included. I think reasonably because we can assume an engine trying to produce maximum effort in any particular cut-off, at speed, will have full regulator. Hence also my comment about the port openings being more or less the same in the two engines. As you mention smaller diameter pipes lead to higher friction losses. It is possible to equate the loss caused by bends etc as an ‘equivalent’ length of straight pipe that is added to the actual length to obtain the total loss. Since both engines were 4-4-0s of similar size, their steam circuits will had more or less the same actual length so we can gain a good approximation of their relative performance at each discrete section in their steam circuits simply by comparing the pipe diameters. If the same flow rate is attempted in two pipes of different diameter the relative pressure drops will be in the ratio of their diameters raised to a power commonly taken as 4.75. Thus a 5-inch pipe at the same steam flow will have a pressure drop that is only around one-third that experienced in a 4-inch pipe. Crimson Rambler

The grate area of the boiler carried by the LYR class 28 was 18.75sq ft, so at 40ihp/sq ft that gives 750 horsepower just making the engines Class 3 for power. The Great Eastern, for example, built a couple of powerful 0-6-0 classes - J19 and J20. On Nationalization the former was class 4F and the other 6F. In 1953 both were reclassified 5F which I guess was when BR introduced its modified system - or were there complaints from the operating people? Crimson Rambler

Sorry I don't know how to put in the necessary link but if you Google Railway Employment (prevention of Accidents) Act 1900 you will find the details. The first six pages can be largely disregarded it is the schedule of twleve items on page 7 that is important - and item 10 concerned the arrangement of tool boxes and water gauges on engines - tool boxes had to be accessible. David Tee told me it included to introducing water contents gauges on tenders. Crimson Rambler

The nature of the lines that engineers such as Stephenson, Locke, Brunel et al built affected the engines that ran on them. This, together with the way the operating people ran the railway, nudged the pre-grouping locomotive engineers consciously or subconsciously into designing engines that suited the characteristics of their railway. For example, the operators of flat routes invited their engineers to develop engines that could haul heavy, fast trains. This necessitated developing high horsepowers at speed which in turn demands a large steam circuit (and not just the valve lap) so the necessary large steam flow will not lose too much pressure on its way to and from the cylinders. On railways, such as the Midland, forced to haul their trains up steeper gradients than their competitors, the size of the steam circuit was of less importance because their engines tended to make their greatest effort lifting the train against gravity rather than overcoming air resistance. Although, an engine that has to haul a up a hill may still have to develop a quite high power despite pulling a lighter train, engine speed usually fell while cut-off was lengthened. Both of these factors tending to reduce the throttling the steam was exposed to, so a smaller steam circuit sufficed. Once a flatter portion of line was encountered the smaller circuit was large enough for the engine to pull its lighter train at as a high a speed as perhaps the more generously proportioned one. We may see this difference comparing a Midland express engine steam circuit with one carried by an equivalent LNWR engine. Both are essentially short-lap engines. While the lap fitted to the George the Fifth was originally 1¼ins because they were fitted with Joy valve gear (constant lead) at 20/25 per cent cut-off the port openings would not have been that dissimilar to those of a 483 class 4-4-0, which were fitted with Stephenson’s gear (variable lead). Thus, we may deduce most of the difference in performance displayed by the two classes was due to the sizes of their respective steam circuits. If a ‘George’ was working with say a pressure drop between the boiler and the steam chest of 15 or 20lbs, then in the Midland engine, the equivalent drop will have been 45 to 60lbs/sq in – hence why red engines didn’t produce high powers at high speeds. Another simple but crucial relationship that affected locomotive performance was the water consumption. Mr Rous-Martin described how a Class ‘T’ 4-4-0 Nº 2596, took the 9-30 am fast Scotch express weighing approximately 300 tons, from St Pancras to Leicester (99 miles) in 111 minutes 34 seconds - gaining nearly 1½ minutes on the booked time in the process. He observed the run could have been 2 or 3 minutes quicker but for shortage of water, which forced Driver Turner to shut in for the latter part of the journey to eke out the remainder. Horsepower estimates confirm there would have been precious little water left in the tender (5-10%) by the time the train had reached Leicester, as was confirmed by Mr Rous-Martin:- “Indeed, I was assured that even more could have been done had the locomotive been fitted with a larger tender, like the ‘2601’ and ‘2606’ Classes” This is enginemanship of a very high order, the more so when we remember tender tank contents gauges were not fitted until the railway companies were compelled to do so by the BOT in 1904. That rash of bogie ‘water carts’ which appeared at the turn of the century were the inevitable accompaniment to building more powerful, saturated locomotives. In the absence of water troughs, engines had to lug 20 and more tons of water behind them, in order to make non-stop journeys of 100 or 120 miles while pulling heavier and/or faster trains. LNWR engines running from Euston typically encountered water troughs every 40 miles or so thereby giving the crews ample opportunity to top up the tender tank. The knowledge that they would not run out gave LNWR enginemen the confidence to work their charges in a way that has whet the appetites of contemporary and later locomotive enthusiasts. The Drawing Office reflected this, by providing (for the day) good exhaust systems, generously proportioned internal steam pipes and large free gas areas through the boiler barrels, which supported high combustion rates. Finally, it was pointed out a 483 class 4-4-0 based on the power calculation was a Class 3 engine, so I thought you might like to see these two tables. The first gives the loads for the Special Limit trains, which were faster, between London and Leicester. The 483 4-4-0s were lumped in as Class 2 engines. The second table records one of these engines taking a Class 3 Special limit Load and gained 3¾ minutes on the way. At this point I feel I have said more than enough. Crimson Rambler

Langridge did comment that poorer quality oil and whitemetal had affected axlebox performance. I don't know when Churchward adopted them but an underpad was tested by Beauchamp Tower when he carried out his famous series of bearing lubrication tests in the 1870s, so they pre-date GJC. Incidentally he found it returned no better bearing performance than top oil entry. Stanier did introduce the oil between about 35 and 40 degrees down from the crown via a pair of grooves. It worked well enough with outside cylinder engines but wasn't so good on inside cylinder engines as their bearing load profile is different. In its last design the Midland introduced the oil at the crown via an elliptical groove with the intention oil could enter while the journal was stationary. The LNER also suffered from hot boxes on some important inside cylinder classes during the Second World War - from memory two were the J38 & J39 . The company prompted the development of a special oil that in effect replicated the older oils used pre-Grouping. Adopted and applied by the LMS to the G1, G2, 7F and 4F it resulted in a noticeable drop in hot boxes. For example in 1942 the G1 and G2 classes a hot box per engine every 8-9 months. By 1946 this had extended to 29 (G1) and 36 months (G2) respectively. But it has to be said this was really a partial return to previous practice because the poor quality whitemetal remained. Crimson Rambler

In Midland days the company's tank engines were not given formal power classifications, so the anomalies Stephen has found strictly apply to LMS and its application. It's possible the LMS may have used a modified curve but I don't have any details. It certainly extended it to encompass more powerful engines higher powers - maybe it altered the power boundaries? I do have somewhere the BR curve which it applied post 1948 to engines from the other three companies. Essentially I seem to recall the method was largely similar save that the free area through the boiler was included as this is an indicator of steaming capability. I will try and find it. Turning to another matter recently raised, the Midland knew a great deal about lubrication and bearings - arguably more than the LMS or Churchward. Deeley with his brother-in-law wrote perhaps the then definitive book on the subject - it was in print for a generation and went through several editions. He also served on an important lubrication committee during the First World War and invented a machine for measuring the 'oilyness' of an oil - an important property necessary for axlebox lubricants. The cheap oil used by the LMS which was deficient in oilyness, was one of the major causes of the axlebox heating that the LMS experienced with the likes of the 4F and other inside cylinder classes - another was substituting a cheaper whitemetal. The Stanier axlebox - despite what Cox might try and have you believe - only lasted longer between repairs because it was bigger - you have more space on an outside cylinder engine for longer bearings. The greater length meant there was more bearing area to wear away before the 'box needed repair. Deeley stated that longer bearings can cause problems on curved lines - interestingly when Cox had his way and gave the Britannia 4-6-2 class a stiff frame, he came unstuck on the Derby-Machester line. The Britannias on that ex-Midland line suffered from broken broken smokebox saddles and loosened frame stretchers. Crimson Rambler

One of the reasons the Midland introduced its power classification was to reduce loco maintenance - particularly boilers, which are apt to suffer if an engine is overloaded. Hence the introduction of train weight limits associated with the different power classes. The idea being any example of particular power class could be relied on to haul a train of weight appropriate to its class limit. When the Midland devised this scheme all of its engines were saturated - it didn't really start superheating until 1912 with the 483 class 4-4-0. Consequently any Class 2 engine had to be able to take a class 2 load - furthermore saturated or superheated they all had H or G7 boilers These had the same grate area so in effect the limit was the 32HP per sq ft of the saturated engine or, for a H/G7 boiler of 675 horsepower i.e. a class 2. I don't know when the power classification scheme was refined to include superheated engines. My suspicion, and it is only that, is that it was not altered until just before the Grouping. Maybe if the Midland needed more Class 3 engines it could have upgraded the '483's, but an advantage of them (and the LMS Class 2) staying in the lower classification was an even lower maintenance cost and something in reserve in service as the ex-G&SWR enginemen found. Crimson Rambler

GWRSwindon At 50mph the engine will travel 5,280ft x 50mph or 264,000ft but considered over a minute this is equal to 4400ft/min. A wheel 6ft 8ins is equivalent to 6.666667ft diameter so the number of wheel revolutions made is given by (4,400/6.66667) X (113/355) where (113/355) is equal to pi. So the wheel is revolving at 210rpm. In that time the piston makes two strokes each of 28ins each. Hence piston speed is 210 X 28 x 2/12 = 980ft/min. Hope this helps. Crimson Rambler

Stephen your boiler pressure differs from mine - I think the Georges ran at 175lbs Incidentally put at its simplest for a two-cylinder simple engine the tractive effort formula becomes:- (cyl dia. x cyl dia x stroke x boiler pressure x factor from curve)/Driving wheel dia all dimensions in inches - hence :- (20.5 x 20.5 x 26 x 175 x 0.29)/81 = 6,846lbs = 3.06tons And the power developed is 6,846lbs x 50mph/375 (a units conversion factor) = 913 indicated horsepower Crimson Rambler

Dear All The following is a copy of the LYR curve the Midland used for its final power scheme:- It formed part of a series of articles on Locomotive Testing I wrote for a railway magazine - until the editor thought they were too technical and stopped it! The following explains how it was used:- Crimson Rambler

HMRS Journal Oct/Dec 2007 Vol 19 issue No. 8 contains a copy of an official Midland drawing of the match waggon for a 15-ton steam crane based at Sheffield together with an article by George Brodie describing how he built it based on a Slaters 19ft underframe kit. Crimson Rambler

David, with the discussion a little earlier on the Matlock Bath Model Railway you might be interested in this:- It was the printer's plate that I had made at work by the visual aids man Rhys from the drawing you produced. Although I was involved in assisting with the running of the museum layout fortunately I was spared the anguish that David (and one or two others) were subjected to. It was a terrible shame the layout could not be saved in its entirety as I think it was in several ways better than the then Derby Museum & Art Gallery layout. Still I suppose two good things came out of it - firstly its existence had prompted the formation of the MRS a year or so before and secondly I believe its high standard gave Mark Higginson the encouragement and impetus to promote the replacement of original Derby layout by the one in the Silk Mill. Hopefully it will not be too long before we can see it again. Crimson Rambler

Possibly the demonstrator was George Brodie - he was certainly doing just that at Doncaster last year. He had some excellent examples of different arc roof carriages built to the diagram book. Crimson Rambler