RLBH

I was referring to the fact that they had a derated 12SVT, putting them just below the Type 3 power band - without the derating, they'd be Type 3s. The same basic engine block wound up – with a lot of development – rated at 3,300hp in the 58s!

Yes, there seems to have been a later evolution of the SVT that got 150hp/cylinder rather than the 125hp/cylinder of earlier models. You can see this in the Southern Region DEMUs – the earlier Class 201s and Class 203s have the 500hp 4SRKT, whilst later 205s and 207s had the 600hp version. I suspect that this is the rating that EE was proposing for follow-ons to the Class 40s with 2,400hp. A 12-cylinder version of such an engine would put out 1,800hp or thereabouts, which is similar to the rating of the 12CSVT in a Class 37. It may well be that the electrics were designed for the earlier engine then someone decided to put the CSVT in and derate it, probably for fuel economy reasons. But that's pure speculation. For that matter, you can see the uprating at work with the LMS Twins and the Bulleid diesels. All had 16SVT engines, starting at 1,600hp (100hp/cylinder) but progressing to 1,750hp (110hp/cylinder) and ultimately to the 2,000hp used in the production Class 40s.

Just a few pages ago! A very odd machine, not really a BR Standard at all and arguably not even a 4-8-0....

Any of the BR diagram books on the Barrowmore MRG website will show that Class 37s had the 12-cylinder version of the CSVT engine. In 16-cylinder form in DP2 and the Class 50s, it gave 2,700hp from 16 cylinders for 168.75 hp/cylinder. The same maths gives you 1,350hp for the 8CSVT; the Portugese Class 1400 actually developed 1,330hp, which is close enough that I'm not going to quibble over it. The 12SVT was fitted in Class 31s, slightly derated to 1,470hp so as not to overload either the electrical or the cooling capacity of the existing locomotive, I'm not entirely clear which.

I think that any viable system to to protect against this kind of accident needs to be based around making the pedestrian aware that the vehicle is moving or is about to move. One such system which several of my workplaces have used on forklifts is a projector which throws an arrow on to the ground a few metres ahead of the vehicle in the direction of travel. It's very effective in warehouses and the like as a way of warning people not to walk in front of a forklift. It's hard to see that working in a rail environment - the surface presumably isn't amenable to it. An audible warning might work, but there again it might not. A low-level warning light might be more effective, or possibly both together. I don't know the rail environment well enough to say. Or for that matter, fencing in the 'safe walking routes' to make it more difficult to take shortcuts!

This is of course true, and there's no reason to suppose that a certain technology or method of working must be effective in one context because it works in another. But equally - if a system is proven elsewhere, then you can't dismiss it simply because the railway is different. It may well be inappropriate for any number of reasons, but they have to be identified and examined before a potential risk reduction measure can be eliminated.

The 37s had the CSVT of the 50s, rather than the SVT of the 20s and 40s, but derated to 1,750hp. At full rating, the 37s would have had 2,000hp, or even a little over - apparently English Electric offered this to BR, who weren't interested. EE actually built what was very nearly a Class 20 with the CSVT engine in the Portugese Railways Class 1400 - with 1,330 horsepower on hand. That would show any of the Type 2s who was in charge, except for the Class 31 which was really a Type 3 with an inferiority complex.

If one takes the view, as many do, that time cannot be scaled, then as long as it takes a prototype train at 100mph to travel 1,524 feet. On this basis, one scale mile per hour corresponds to a speed of 0.02 feet per second. At scale 100mph, the model is travelling at 2 feet per second, and will take ten seconds to cover 20 feet. At scale 30mph, 35 seconds, and at scale 60mph, 17 seconds. I have taken the liberty of rounding off to the nearest second! If one chooses other scaling laws, other answers are possible. How one should scale time is another question altogether, but one that needs to be answered. Even choosing not to scale it is still making a choice. Suppose you are a sufficiently skilled and dedicated modeller that you build a perfect 4mm:1 foot replica of a pendulum-driven clock. How often does it tick compared to the prototype clock? The scaling law to get that to work out is different from the scaling law needed to make clouds of smoke from your smoke generator to billow in a prototypically correct manner!

When you look at what they were actually expected to achieve - standard gauge railways have done as much or more. Goods trains were to reach maxima of 16,000 to 18,000 tonnes (1,200 metres long) at 100 kph - the locomotive you've shown would handle such trains on non-electrified sections. That's the kind of performance now being achieved on standard gauge railways in North America. Shorter-distance passenger trains (i.e. German domestic services) were to use multiple units with 1,000 to 1,600 passengers, capable of 250 kph. That's achieved or exceeded on many national high-speed rail systems today. The long-distance passenger trains aren't directly matched, but that's partly because the demand for them isn't there - almost anyone wanting to travel that kind of distance flies instead. Something approximating them in terms of accomodation standards could be done with double-deck standard gauge stock, though you'd need to run multiple trains to handle the same number of passengers. The whole thing is utterly barking, with huge amounts of excess weight (load being 75% of gross weight on the goods wagons, for example), but fascinating for it.

I have some diagrams of proposed rolling stock for the Breitspurbahn - the enormous track and loading gauge permits proportionately enormous stock. Which is of course enormously heavy, so that even with a 35-tonne axle load almost everything would be running on 8-wheel bogies. The 200-tonne capacity bottom-unloading coal hoppers actually had an underframe longer than the body to have enough space for the wheels. Saner engineers feld that a four-track standard-gauge railway made more sense, but designing a gigantic railway to satisfy the Fuhrer's whims was probably preferable to serving as a rifleman on the Eastern Front.

Not the case at all! Certain oscillations of the running gear at high speeds are difficult to control if the wheelbase is small compared to the gauge, so broad-gauge lines would have serious issues at high speeds. That's one of the reasons why Spanish and Indian high-speed rail projects are going for standard gauge. Purely from that perspective, the narrowest gauge possible makes sense, which probably goes some way to explaining enthusiasm for the concept of a high-speed monorail. Other considerations, of course, prevent the gauge from getting too small - countries with narrow-gauge systems have also found standard gauge preferable for high-speed rail! Tellingly, the Shinkansen system is standard gauge, despite being a completely clean-sheet design and not having to worry about interchangeability with any other rail networks. There's probably an optimum gauge for any given application, but available evidence suggests that for most applications the theoretical advantage of that optimum gauge over 4'8.5" is very small. The Russians aren't changing gauge for their high-speed rail projects, which suggests that 5' and 4'8.5" are both close enough to the optimum that it doesn't really matter which you use. Of course, the designers (non-railway engineers) of the Bay Area Rapid Transit system also decided to start from a clean sheet and came up with 5'6" as the ideal gauge for their purpose. But on the other side of the coin, they also didn't discover the importance of coned wheels, so I wouldn't place too much emphasis on their findings. For the contrary viewpoint, look up Robert Fairlie's Railways or No Railways, in which the inventor of the eponymous locomotive advocates for gauges as narrow as 2'6"!

They may still be authorised to run at a speed they aren't physically capable of, mind you....

Inside cylinders couldn't be quite as big, and outside cylinders could be a little bit bigger - at least assuming the loading gauge remained about the same!

Straying quite a long way from Class 17s, but that DMU (really a DEMU) was a prototype for what ultimately became the Swindon Inter-City DMUs. In hindsight, the combination of BTH electrics and the Paxman ZH probably wouldn't

A Big Boy was once hand fired when the mechanical stoker failed - keeping the fire fed involved the fireman and head end brakeman taking a shovel apiece and throwing coal into the firebox as fast as they could for some considerable distance/ Of course, in that case they had a steam table to distribute the coal anyway, so precisely placing the shovelfuls wasn't so important - but hand firing a 150 square foot grate is impressive nonetheless!

Someone did suggest an alternative 1922 Grouping which did this, and put the Hull & Barnsley into the pot as well, giving the resulting railway a pretty extensive system. The suggestion also split the LMS into two groups - one built around the LNWR, LYR and Caledonian, and the other around the Midland and G&SWR. The intent there being to preserve genuinely competitive routes, rather than grant each company a monopoly over a particular region. I have doubts about how well it would have worked, but it would certainly lead to the Grouping-era railway developing quite differently and some very odd sights to our eyes.

I understand that in practice it's cyclic loading due to turbulence (there's always some turbulence) that drives fatigue life, which is largely a function of flying time. Except that some flying hours are more equal than other flying hours. Aircraft (and ships, for that matter) can be fitted with gadgets that measure the stress cycles in the main spar and convert it to equivalent cycles at a certain standard stress level. Rather highlighting the point about aluminium failing under any cyclic stress at all, the Vickers Valiant is of interest. After several fell apart in flight, the main spars were examined and found to have severe fatigue cracking. Vickers had built a number of spare wing spars which had never been flown - and they, too, had appreciable fatigue cracking. The properties of the particular aluminium alloy used on the Valiant were so poor that thermal and handling loads for the spares were enough to cause them problems.

I believe, though I'm happy to be corrected, that BR Mark 1 coaches were originally expected to last for 40 years with a major refurbishment at the 20-year mark.

That looks like a fantastic plan for what will hopefully be a lot of fun to run trains on when all the track is down. Personally, I'm particularly taken by the fiddle yard layout, as it's not far from being a fully functional (if small) goods marshalling yard divided between directions. That principle alone looks interesting for wagon-shuffling, whilst still allowing for passenger services to run through without stopping. One for me to bear in mind for that distant future date when spatial and finanical constraints can be relaxed!

There's a line of thought in some quarters that weird speed limits are better observed because drivers think something like 'that's odd, there must be a good reason for it to be like that' and watch their speed a bit more. That's one of the reasons why roadworks often have similar limits for works traffic. The other, which doesn't apply to railways, is that it helps clarify that it's a limit for works traffic and not for the road users on the other side of the line of cones.

It's credited to an A. C. Sterndale, seemingly a railway photographer writer also credited as Tony Sterndale - so I assume the 'A' is Anthony. He worked variously in the Swindon drawing offices and testing team, so would have had some familiarity with locomotive design. The 4-8-0 does seem to be Swindon influenced in design - the choice of that wheel arrangement over a 2-8-2 in particular being consistent with GWR preferences for 4-6-0s over Pacifics. I would suggest that the 4-8-0 is a private 'flight of fancy' from Sterndale in the same vein as those we know about from Durrant or Powell. Such schemes are endlessly fascinating as they illustrate the thoughts of those who were there about what they would have liked to have done, given a free hand.

One imagines Beyer Peacock were desperate for a British railway company to buy some Beyer-Garratt locomotives. It really doesn't help an export effort if you can't sell your product at home!

How sensitive are transformers to frequency anyway? No doubt they can be optimised for a certain range, but I'd have thought one designed to convert 50Hz supply would work, though perhaps less efficiently, at 25Hz.

Being really pedantic, you want the longest fixed wheelbase - for bogie vehicles, it's the distance between bogie centres that counts. Of course, on the modern railway there's a movement to either lower train floors to 915mm, or raise the platforms to line up with the doors, to facilitate level boarding of wheelchairs, prams and so forth. I've never quite understood why that wasn't thought to be a good idea when the railways were first built.

Given that the parameters of the standard formulaare limited to the number, bore and stroke of pistons, the boiler pressure, and the driving wheel diameter, I'm curious how speed or free gas area might appear. If you have another formulation featuring these, please do share it. Sadly Kew is about 400 miles away, and my employer takes a dim view of disappearing off to London to check such things. Certainly the LMS system adjusted for speed - strictly, for piston speed - by means of an estimated mean effective pressure as a proportion of boiler pressure. There's a copy of the relevant curves - as well as the BR formulae and associated tables - in Ransome-Wallis's Last Steam Locomotives of British Railways. I've always understood that it was primarily a management figure - Control didn't necessarily need to know precisely what locomotives a shed had on hand, just what trains they could pull. Any locomotive with a power class of 4F ought to be able to handle any freight train with the corresponding rating, and so forth.