#slime folk

More Details on the "Foresight" Class

Advanced Steam Locomotives were the result of a global oil crisis that began on Gymnome in the late 2320s that made Diesel engines first uneconomical, then almost unusable. After a period of bringing museum steam locomotives out of mothballs and modifying existing designs, the Foresight class is among the first "third generation" steam locomotives, designed with modern engineering principles from the ground up.

Advanced Steam engines, including this class, are designed with ease of maintenance and operation as well as high efficiency. The controls are electromechanical with an electronic control stand in the cab, similar to what you'd find in a Diesel, and it can be hooked up to other locomotives as a multiple unit. Some are even equipped for remote control running.

The engine is a compound Mallet, which uses the steam twice in pairs of low pressure and high pressure cylinders to make better use of its expansion. The firebox is a gas producer combustion system which breaks the fuel (either coal or biofuel, stored on a hopper atop the saddle tank) down into gasses, which are then burned at high efficiency. This produces more ash, but much less soot.

The locomotive runs at a high boiler pressure of 25 bar, and uses a superheater, since hotter, higher pressure steam expands more efficiently. However, this produces arguably too much pressure for the locomotive to use given the size of the cylinders. If it could use all of its tractive effort, it would be able to exert a whopping 243 kN of force. In practice, it would wheelslip long before thin. Although the onboard computer would identify and attempt to prevent a wheelslip, it would reduce in a lower throttle setting, which reduces the effective pressure.

Instead, the Foresight's cylinders are deliberately oversized so that it can be run with a higher cutoff, that is, closer to neutral gear. When running near neutral gear, steam is put in the cylinders only briefly during each stroke, which does less work per stroke but more work per unit of steam, therefore making the engine run more efficiently. To facilitate this, the expansion link on the valve gear has been cut short, limiting the cutoff to 30% in either direction, although starting cutoff is nominally 26%, which means it is over twice as efficient as an engine with the same tractive effort but working at full cutoff.

The useful tractive effort is about 60 kN.

Process:

This locomotive's story starts in July 2024, when I drew this image:

of a Gymnomi Advanced Steam locomotive based loosely on the Argentinian LVM800 (Modern Steam Locomotive 800) concept by one of the biggest (and most successful) late proponent of steam, L.D. Porta.

My original version of the Gymnomi Advanced Tank Engine took the hopper-shaped covered coal bunker on top, and the basic design of the platforms on front and back, but adapted it to an overkill 0-6-6-0 Mallet design in true Gymnomi articulated loco design fashion. In retrospect I probably should have made it an 0-4-4-0, oh well.

In December 2024 I learned how to use Blender with the help of my friend @msasterisk, and produced this model:

By January that model was used in our new game, Train Puzzle dot exe (title then pending).

MsAsterisk later made this pixel art animation depicting the locomotive scrolling through lovely pixel art scenery based on that found in the original drawing.

And at some point I drew the inside of the cab.

This (quite self indulgent) art was done by placing the engine's game model next to my model of Thomas and tracing the result. It let me refine the look of the engine somewhat and include detail that wouldn't have fit into the game model. It's at this point that the loco gained Southern Valve Gear.

This alternate version was made showing the engine crew characters from the game. I now realize that the characters are grossly under-scale here. (The game's name was briefly Railway Misconductor; it is now Train Misconductor).

During the development process for the most recent milestone version, the resolution was slightly raised, which let me add a little more detail to the basic car frame model, including a 3D modelled truck rather than a box with a photo of wheels on it. But then, the box-with-wheel-drawings original 3D model was looking pretty archaic, so a few days ago the loco was redesigned. This let me fix some proportion issues I was annoyed by, and add a little more detail.

And I liked it so much I raised the game's resolution even more.

That brings us to the drawing at hand:

I started with this render of the new game model of the engine, and traced it, adjusting a few proportions to fit a realistic style and adding lots of detail.

I made heavy use of FireAlpaca's perspective tools. The wheels were done by first drawing two wheels on a circle, and then copying and squishing them to fit the elliptical shape they present to the viewer. The brake pump was given lots more detail, and the dynamo was added (previously I had assumed the dynamo might be hidden away because it's so noisy, but there's not really a good place for it.)

Then came brake rigging, sanding gear, and a blastpipe on the front engine, and the connecting rods, crosshead, and main rod on the engines. Cab detail taken from the old cab view drawing was added as well.

Here's the more or less final line art:

Note the holes in the side of the firebox. These are to let in air above the coal grates, as part of the Gas Producer Combustion System design. (although not the one from the LVM800).

There's also number boards on the headlamps. They were suggested on the previous drawings, but now they have an actual number (11513).

The LVM800 ancestry is a little more visible in this version, with the modified coal hopper roof doors and the sloped cab walls.

Then came the scenery, which was made in layers to replicate aspects of both MsAsterisk's pixel art scene and the original drawing it refers to, as well as a few of the other tree assets currently in game.

It was here where I went to sleep (at 5 AM last night). I got 4 hours of sleep and got back up to finish the drawing, so as you can imagine I'm a little tired as I type this. :P

By 11:30 today the solid colors were done.

And at 1:20 the rendering for the first variant, the clean yellow livery, was done:

Clean and factory fresh! Time to make her TIRED! The SLYM-11513 has only been in use for a few years by this point, but it does dirty work and the maintenance department is too overworked by all the new steam engines (which are harder to maintain than Diesels, even with Advanced Steam) to reliably clean the darned thing.

So the weathering was added, and the loco was finally complete!

But it was still missing one thing:

Can't have a Gymnomi train without a Gymnomi Slime crew!

Finally, some livery variants were prepared, which can be seen here:

There's some more livery variants I want to draw but they would be more complicated to pull off, so they can wait.

Here's some transparent versions

And finally a lineless version. The drawing wasn't designed to be seen this way but it's kind of interesting how close it is to looking good.

What's next for this engine? Well in addition to being part of a very fun shunting puzzle video game, I want to model essentially this drawing in blender, as a future project. Essentially going from traced blender render to high quality drawing back to blender render, but this time with a ton more detail. This would mostly be just a for-fun project, but it's possible I could mod it into other existing train games.

appendix: a fun render i made last night.