I had never purchased a MDC/Roundhouse "Old Time" 2-6-0 because they were kind of odd— high-drivered, with a high-mounted straight fat boiler. (Same boiler as the kit-maker's 2-8-0.) It was hard to find a prototype that resembled it. Certainly, it wasn't a typical 2-6-0 for my 1880–1890 modeling period. It was a common kit engine from the 70s through the 90s, and to this day you can find dozens on ebay. (Athearn now owns the old MDC/Roundhouse tooling but doesn't release the engine as a kit any more.)

I figured that one day I could use the mechanism to kit-bash a better-looking engine, and that's the way matters stayed until one day I saw...

I have a weakness for "junker" locomotives. When I saw pictures of this basket case on eBay, I suspected that someone had taken extra care in building the kit— MDC's plastic crankpins had been replaced by screws. Could it be that this fellow had once been a dependable runner? The picture shows the state of the engine as received— trashed boiler, broken cab, no tender. When hooked up to alligator clips, though, the mechanism ran well. Score!
This is the kind of engine I wanted— a big, dual-use (freight and passenger) high-drivered mogul of the 1890s. These engines commonly had wagon-top boilers, spacious cabs, and comparatively small tenders. Moguls were usually used as low-drivered freight haulers, but for a brief decade or so around the time of the Columbian Exhibition, high-drivered moguls were used for heavy passenger and fast freight trains.
Needed a wagon-top boiler. Stole one from an unbuilt Mantua Rogers 4-6-0. These models are way oversized for HO, meant to be 1/72 OO scale (or larger) rather than 1/87 HO scale. However, the wagon-top boiler is smaller in diameter than the original one from Roundhouse. It's too long, though. So, after carefully measuring, I removed a section.
I stripped the boiler of unnecessary detail, patched it with Squadron white body putty, and cast a new internal weight from Cerro Bend low-temperature pot metal. I narrowed the running boards and sanded the boiler to a polish finish. The engine frame got a new brass pilot from Precision Scale. Driver wheels got thin styrene sectional counterweights glued on to hide the 20th-century crescent-style ones.
Things were painted as I went along. I mixed a small portion of gunmetal with steel, using Testor's Modelmaster paints, to get a good-looking Russia iron gloss for the boiler. The gilt striping on the Mantua domes is the underneath brass showing through. I built up the firebox inside the cab and added a backhead casting from a forgotten supplier. The cab was made from Evergreen plastic styrene.
I filtched a plastic tender from an old Pocher 2-4-0, filled it with lead car weights, and mounted it on an old set of MDC/Roundhouse Fox tender trucks. The tender wheels are directly wired to the motor. One truck takes current from the right rail, the other from the left. A Tomar track slider on the engine's insulated driver side lets it pick up current from both rails too.
Parts go on, parts come off. Things are test-fit, then taken off and corrected, then test-fit again. The boiler-top details are a mix of old plastic MDC/Roundhouse parts plus Cal-Scale and Precision Scale brass castings. Most were already resident in the box I call my "brass library."
I add engine crews to my locomotives because I have a hard time watching them run with empty cabs. I think these figures were from Woodland Scenics. Here's the project with finished details and paint, ready for decaling. Decals were made with Adobe Illustrator and laserprinted on white decal stock.
Nope, no "weathering." Rustbucket locos were a feature of the penny-pinching twentieth century. In the 1890s, engine crews took pride in their machines, cleaning them daily and going over their shiny surfaces with oily rags.
Even before breaking in, the #169 proved to be a reliable slow runner and was chosen to run the first train on the Miskatonic RR. It's still a BIG loco for 19th-century HO, but it might turn out to be one of my favorites...