A MOSS-Image LoRA for photos of North American steam locomotives: famous preserved engines, classic wheel arrangements and the railroad scenes around them. Released as v0.5. It's good on the big-name mainline engines, liveries and scenes, but a few classes aren't right yet (see Known limits).

What it does well

• Famous engines by name: Union Pacific Big Boy 4014 and 844, Norfolk & Western 611 and 1218, Southern Pacific 4449 Daylight, Canadian Pacific Royal Hudson, Santa Fe 3751, Chesapeake & Ohio 614, Nickel Plate 765, Milwaukee Road 261, Reading 2102, PRR K4s, CN 6060

• 19th-century 4-4-0s: The General, the Golden Spike engines, generic American types

• Wheel arrangements: 2-8-0, 2-8-2, 2-8-4, 4-6-0, 4-6-2, 4-6-4, 4-8-2, 4-8-4, switchers, narrow gauge (Rio Grande K-27/K-36, Durango & Silverton)

• Railroad scenes: smoke and steam, excursion trains, bridges, mountain grades, depots, museum halls, cab interiors, black-and-white archive photos

• Works on both MOSS-Image Base and SFT. SFT gives sharper, better-composed results.

How to prompt

• Start with the engine's name and type, then describe the scene, e.g. "Union Pacific Big Boy, a 4-8-8-4 articulated steam locomotive. Three-quarter front view of Big Boy 4014 leading a long freight train across a Wyoming plain..."

• Short prompts work too ("Union Pacific Big Boy, a 4-8-8-4 articulated steam locomotive.").

• LoRA strength 1.0.

• Settings used for the samples: 40 steps, CFG 3, euler / sgm_uniform, shift 5, 1216×832.

Known limits (why this is v0.5)

• Geared logging engines (Shay, Heisler, Climax) come out as ordinary rod engines, often with the name painted on the cab.

• Southern Pacific cab-forwards come out with the cab at the back. Challengers often look like a single-unit 4-8-4.

• Road numbers and lettering are often garbled. That's partly a limit of the base model.

Training

• About 2,900 photos (mostly Wikimedia Commons) in 46 classes, each captioned three ways (long, medium and short MOSS-style captions).

• kohya sd-scripts, rank 64 / alpha 16, about 13,500 steps in total.