Southern Railways "Schools" V class [WIP]

[Gumboots]

Starting modelling this little rocket, just for fun. Have got this far with the CAD.

Schools_out.png (37.92 KiB) Viewed 33020 times

Haven't started hex coding yet but will make a start on the basics this week.

I like this as a contrast to the Berkshire. The idea of a Berkshire was "Hey if we stuff two more wheels under the rear of a 2-8-2 it'll make a really good big freight engine". The Schools class 4-4-0 was the exact opposite: "Hey if we chop two wheels off the rear of a 4-6-0 we'll have a really good little express engine".

They had to be short to fit on the turntables on the relevant lines, but they had to be seriously fast to give good express serivce. What Maunsell did was to take a 4-6-0 and cut down the length of the boiler. The firebox stayed full sized. The boiler itself has a length of 11' 9". The firebox is a whole 9 feet. For comparison, the firebox of an A1 Berkshire is about 13 feet long and the boiler is about 26 feet. So the Berkshire, which supposedly had a really big firebox, had one that was about 50% of the boiler length. The Schools class firebox was 77% of the boiler length.

Short and fat boilers are more efficient too (the firebox gases cool off more in longer boilers) and being a 4-4-0 it had really low internal friction. The overall result was that the Schools class were known for being free steaming even on poor grades of coal, really easy on the fireman, and capable of keeping up with most 4-6-0's and 4-6-2's. The short wheelbase meant tight curves were no problem, but stability at high speed seems to have been fine.Throw in great reliability and fewer parts to maintain and you have a really good little locomotive.

Presumably the shorter boiler being cooked up by a comparatively huge firebox would need water fed into it faster, but this doesn't seem to have mattered. Overall consumption per mile wouldn't change, just the feed rate to the boiler. The only catches were that the axle loading was taken as high as possible, meaning some branch lines weren't accessible, and the starting tractive effort was a bit much for the adhesion, meaning the engineer had to handle standing starts with a bit of care. Once rolling they seem to have been fine, and were known for good performance on hills.

So yeah, these little things are cool. We gotta have them.

[AdmiralHalsey]

Hey Gumboots. I know that your ultimate goal is a roster of all steam engines right? Well seeing as you would need to make some fictional locomotives for the the later period I think http://www.internationalsteam.co.uk/tra ... dern50.htm and http://milwaukeeroadarchives.com/Econom ... nPaper.pdf would help some.(The second one is the the study by H. F. Brown mentioned in the Age of Steam Phoenix Rising scenario.)

[arop]

I'm looking forward to use the 4-4-0 "Scools Class" for minor jobs in some of my future maps. A new and improved 0-6-0 DX goods is also desireable. Everything isn't about BIG American steam engines for BIG railroading. In RRT3 there is a total lack of tank engines (seldom used in the US), but it's all up to you! I shall not try to push a volunteer doing a GREAT job

[Gumboots]

Minor jobs? With a top speed of 95 mph, good fuel economy, fast acceleration, great reliability and reasonable performance on grades I think it'll be useful for fairly major jobs. I'd certainly prefer it to a Mallard for a lot of things.

As it turns out, I've sort of shot myself in the foot with this project. The basics of the Schools class are really simple (4-4-0, parallel boiler) but once I started getting into detail they aren't so simple at all. Will probably end up being about as much work as any other locomotive, but they're cute and cool so I'll do it anyway.

Tank engines are hard to get enthused about because they are usually ugly. This is probably why nobody has made one. People like to make cool things. I might make one or two eventually, but there are other things I'd rather do first.

Hey Gumboots. I know that your ultimate goal is a roster of all steam engines right? Well seeing as you would need to make some fictional locomotives for the the later period I think http://www.internationalsteam.co.uk/tra ... dern50.htm and http://milwaukeeroadarchives.com/Econom ... nPaper.pdf would help some.(The second one is the the study by H. F. Brown mentioned in the Age of Steam Phoenix Rising scenario.)

Had already seen those. TBH the first candidates for 21st century steam would be the updated Peppercorn A1 4-6-2 Tornado, and the updated version of the P2 2-8-2 that the same bunch are building. Those are two of my favourites engines anyway, and if I model them once then I get to cover two completely different timeframes just by tweaking the stats slightly. This is good if you're a bit lazy.

[AdmiralHalsey]

TBH the first candidates for 21st century steam would be the updated Peppercorn A1 4-6-2 Tornado, and the updated version of the P2 2-8-2 that the same bunch are building. Those are two of my favourites engines anyway, and if I model them once then I get to cover two completely different timeframes just by tweaking the stats slightly. This is good if you're a bit lazy.

Yeah I just love the Tornado. She proves IMO that if you build it right steam is still viable. Oh and for a stop gap loco to help bridge the period between the the end of steam and the Red Devil try making http://en.wikipedia.org/wiki/BR_Standard_Class_8(With the fixes to the builder errors of course.)

[Gumboots]

Looks like a good candidate.

I've been thinking about this availability date thing. Arguably, and somewhat dodgily, you could say that if any example of a locomotive is currently running somewhere in the world, the thing is still "available". It will have needed renovation/restoration to a degree, which means making bits for it, and if you can make bits for it you can make the whole thing. So by that line of seriously suspect reasoning a Schools class is still "available" in 2014, as are a lot of other steam locomotives.

[Hawk]

Has anyone read this article, written by our own William Sherrick?

http://hawkdawg.com/rrhist/am.htm

[Gumboots]

Hadn't seen that before. Interesting stuff.

[Hawk]

There's one or two more articles on this page that might interest you.

[Gumboots]

Back to the Schools class. I've got the CAD model a bit more detailed now. Still haven't started on the hex. I'll probably just code up some wheels to start with.

I was looking at how PopTop coded other 4-4-0's in the game. What they did, for all examples that actually have a front truck*, is set the front track attachment point halfway along the front truck, and the rear one halfway between the pairs of driving wheels. This makes sense for the rear one, but I want to try shifting the front one around. I have an idea that if it's set back or forward a bit the truck might appear to do a better job of following curved track. The default 4-4-0's hardly show any change in front truck angle around corners.

*Some, like the Duke, just have all wheels fixed to the chassis. The "front truck" is just graphics, and doesn't actually exist as a seperate unit.

Latest_1.jpg (42.76 KiB) Viewed 32984 times

Latest_2.jpg (46.91 KiB) Viewed 32984 times

[AdmiralHalsey]

She's beginning to look like a great looking steamer.

[RulerofRails]

Has anyone read this article, written by our own William Sherrick?

Thanks, Hawk. I hadn't searched through that part of the site yet. Just read it and it is excellent. I haven't seen such a short, concise presentation of why steam really disappeared. Thanks to him and thanks for keeping it on your site!

BTW, Gumboots, the engine is looking good.

[Gumboots]

TBH that's partly why I chose it. It's a good looking class. It's pretty hard to make the thing look bad if you just follow the plans.

I've been researching this quite a bit, trawling all over the place for information, just because I want to understand how they were really put together. They're quite an interesting solution to a design problem.

They were originally built for the Tonbridge to Hastings line, which has a number of unusual characteristics. One is that it starts with a tight curve leading into a rather stiff grade of around 2% (varies between 1 in 47 and 1 in 53). The line crosses the Weald, which has altitude differences of up to 600 feet. The ridges run mostly east to west, while the line generally runs north to south. The idea of the Schools class was that they could haul the local express trains without requiring assistance. That meant they needed to be able to handle grades well.

Due to trying to get across that country with reasonable grades, the line has a lot of tight turns and switchbacks. So, althoough the short turntables on some lines were the primary reason for the short wheelbase, it was also a big advantage for dealing with the corners between Tonbridge and Hastings.

The oddest thing about that run though is the tunnels. They were contracted out when the line was built in 1852, and the contractors cheated. Instead of building the tunnels with the required six layers of brick, they only used four. This was discovered in 1862 when one of the tunnels (Wadhurst) fell down.

Reboring and rebuilding all the tunnels from scratch was considered too expensive and time consuming, so the railway decided to add the extra two layers of brick on the inside of the existing tunnels. This worked, but obviously made the tunnels smaller. So, 75 years later, when Maunsell had to design the Schools class, it had to fit a loading gauge that was unusually small, and was the result of fixing the mess left by dodgey contractors cheating the previous company in the previous century. The loading gauge was so tight that the rails in the tunnels were checked frequently to make sure they hadn't shifted at all, because a couple of inches off might mean a stuck train.

That had several results. The reason the upper sections of the cab are angled in is because they had to be. It simply wouldn't fit through the tunnels otherwise. This then meant that the windows in the front of the cab had to move inwards with the sides, which meant the preferred Belpaire firebox wasn't feasible because the crew would have no way of seeing past it. So, the class had to be built with a parallel boiler and round top firebox.

The boiler had to fit between the top of the tunnels and the large drivers the engine needed for high speed express service, so that restricted the width of the grate. That explains the decision to cut down the boiler length but not the firebox length. Although the Schools class firebox is around half as long again as an A1 Berkshire's, when just comparing firebox length to boiler length, it had to be narrower. In terms of grate area compared to boiler size, the two are probably about equal. Lima weren't the only ones who knew about "Superpower".

Another interesting thing about this class is that, despite being a three cylinder, they didn't have reliability problems with the valve gear for the middle cylinder. They had to be three cylinder to get the required power within the loading gauge.

Instead of using Gresley conjugated shenanigans or some of the other options, Maunsell just gave the middle cylinder another Walschaerts linkage of its own. This was nice and simple and reliable, like Walschaerts gear usually is, so no problems. The vertical bulkhead beneath the front of the smokebox (between the angled ends of the main frame plates) was totally removable for access, so getting at stuff when you had to wasn't that hard. The middle cylinder was just in a line with the outer two (not crammed up against the smokebox like some other three cylinder locos) which meant it got plenty of cooling air from underneath, and again tended to make maintenance less difficult.

Net result was a grunty little three cylinder that was totally reliable and fairly easy to service, would go up hills well hauling express trains of moderate weight, would fit through any tunnel and go around any corner, and could wind out to 95 mph on the flat. Win.

They ended up building forty of the things and using them all over the place right through until the end of steam, just because they were so good.

[JeremyH]

Ahi ahi ahi! I almost dying of happiness to see a Southern Railway School class in production! That's just incredible. Oh the trains I'd utilize that on!

While we are on the topic of exceptional British locomotives, I wonder if you might ever consider building a BR Standard Class 9F? The 'spaceships' represent the pinnacle of British locomotive design - everything from pulling 1000+ tonne freight to (occasionally, granted) leading the Scotsman at 90 mph.

A thought about tank engines: the GWR 5700 series could be a good candidate.

[Gumboots]

Well it's not actually "in production" yet. They're awesome cute little hot rods and I'll finish it at some point just for fun (even though that period is already well supplied with British express). At the moment I've been sidetracked into fixing the bugs in the existing 1.06 steam roster.

Yes, I would consider doing a 9F at some stage. The GWR 5700 doesn't really appeal to me though. I realise they're kinda iconic and all that, but just not really my thing. There are too many other locos I'd prefer to do first.

One I might do for light relief is a Midland Spinner, just because it'd be a fun thing to have and would be really easy to make from the default Stirling model. Basically, ditch the outside cylinders and steal a decent steam dome from somewhere else. Apart from that and the livery there wouldn't be all that much to it.

[JeremyH]

A decent steam dome! With a flatter one and inside cylinders, that could past for just about any British 4-2-2: Spinner, Great Eastern Holden 1898 single etc.

Anyway good to see some inspired locomotive design going on, even if in formative stages only!

[Gumboots]

K, plan of attack. I know I'm supposed to be behaving myself and debugging 1.06 locos, but I really want to do the SR Schools class. I've just totally fallen in love with the things. Dunno why. Probably some form of mental illness.

Since I'm currently putting the tank engine on the backburner, due to general lack of interest in them anyway, what I reckon I'll do is develop the Black 5 and Schools class simultaneously. This isn't as daft as it sounds. If you check out how they're put together there is a fair amount of similarity. The main differences are that the Black 5 has the tapered boiler and Belpaire firebox and no wheel arches, but these aren't a big deal in the total scheme of things. Running boards, cylinders, cabs, tenders, funnels, steam domes, etc, etc have a lot in common, so if I develop them together it should work out pretty well.

Black_5_vs_Schools.jpg (45.83 KiB) Viewed 29700 times

By switching the Black 5 firebox for the LNER style, that should also set things up well for revamping the A1 and V2. They would also need slight running board tweaks to get the LNER S curve near the firebox, but apart from that they're quite similar to a Black 5, and differ from each other mainly in cab shape and wheel arches (or lack thereof).

Obviously I'll have to finish Gunter das Nontankenginen first, but I'll schedule the Black 5 and Schools class next.

[Blackhawk]

Good luck with them. Should be nice to see a decent looking Black 5 without it glowing at night.

[Gumboots]

I have been thinking I should have another crack at this. Only one problem. I have completely forgotten how to make new engines (even though I've done it before) and there aren't any decent instructions anywhere I've looked.

Someone refresh my memory for me. I think it has something to do with using the default RT3 Train Skin utility to generate the profile and beauty shot imb's as if they were for a skin for an existing engine, then packing those into a PK4 with the other files.

If I get it figured out again I am going to effing well document it this time. In English even.

[Gumboots]

Hey, I got this thing partly modelled in Blender now. I had a brainwave. The CAD app I was using before will export as Wavefront.obj and Blender imports that just fine. Unlike when converting RT3 .3dp to .obj and inporting, going straight from my CAD app to .obj then to Blender doesn't stand the loco on its nose. It's right way up, just swapped end for end. A simple 180 degree rotation sorts it nicely, then it just gets saved as a standard .blend file.

The only catch is the exported .obj mesh has an insane number of vertices and faces, way more than the original model, so I've been going through it and knocking it back to where it should be. This is a bit tedious, but OTOH is a good way to familiarise myself with Blender's gui, and saves some time with dimensioning since I already had the main parts set up accurately. Once I get it mostly sorted I'll break it own into components for export to .3ds, then look at getting that converted to .3dp.

Pic attached.

Schools_class_Blender.jpg (38.33 KiB) Viewed 29504 times