"Good Lord, Holmes! Why would anyone want an HO model of a Peruvian locomotive?"

"Pure sentiment, my dear Watson. Our client grew up in Lima before coming to America and making a name for himself as an outstanding violinist, music teacher, and HO collector. He used to see this very locomotive often, hauling tourist trains on the renowned Lima-Huancayo line, highest in the world."

The question being— where could I get such a model for our friend Cesar? The "Andes" class 2-8-0 was one of the most famous locomotives in South America. For forty years they chugged up the impossible grades and twisted switchbacks of the standard-gauge Ferrocarril del Centro, highest railroad in the world, starting at sea-level Lima and ending 206 miles later across the Andes in Huancayo, on the other side of a tortuous 15,692-foot pass.

The sturdy little engines resembled their North American cousins, despite having been built in England by Beyer-Peacock. One of the class, #206, was preserved and pulls tourist trains to this day.

All this unfortunately means little to the US modeling community. A cursory search of the brass Brown Book turned up nothing. An internet search turned up a European company that made an unpowered N scale collector's toy— but there was nothing in HO. Reference materials? Books and magazines? Zip.

After scanning and scaling up the drawing, I discovered that engine was very similar in size to an old friend— MDC/Roundhouse's (Now Athearn's) old-time 2-8-0 (below). Well, if you want a one-of-a-kind model locomotive, and you have no good drawings or measurements, "similar" means "close enough."
The evidence accumulates: photos and video shots off the internet.
The MDC/Roundhouse engine was sold as a kit for many years and I've built a few of my own. For around a hundred bucks, you can still grab an unbuilt kit off eBay. That's what I did. It arrived inside a week. Armed with my Roundhouse kit and my Precision Scale parts catalog, I began to build a loco.
There were no easy solutions for building the tender. Finally, I took the weighted tender frame from a Mantua Rogers 2-6-0 and build a new styrene shell around it. The Symington tender trucks came from Bethlehem Car Works. I used more PC board and .002 brass shim to make wheel wipers for the tender. With multiple points of electrical contact on each side of the locomotive and tender, the model hops through switches without hesitation, and really crawls when the throttle is low.

There's no DCC or sound, but plenty of room in the tender for that later. Cesar was happy to get his locomotive. I was happy to get back to 19th-century modeling.

The real engine never had one paint scheme. Every new photo I found showed it painted slightly different from the previous one. There were also lettering and logo changes as the railroad went through changes of ownership. The red wheels and yellow handrails come from recent photos. In the end, the loco looks very American— but the paint job is very British. I made the tender and cab-side decals using Adobe Illustrator, then tried really hard to match the shade of green with my airbrushed Floquil paints. Everything got a coat of Testor's varnish in the end.
Click on the pix for larger versions.
"I say, Holmes, what lovely scenery here in the Andes! Have you noticed the rocks?"
"Sedimentary, my dear Watson. Sedimentary."
There are more locomotive-building stories on the Miskatonic RR page . . .
Once the parts arrived, I stripped the boiler of all its features and began fitting the new Precision Scale parts— domes, stack, headlight, bell, whistle, generator, air pump, check valves, piping, and other details. I also got a spoked pilot wheel set and brass cab roof. Most important, I swapped the original cylinders for Precision Scale's #31193 cylinder block and added their #31206 crossheads and their #31528 Walschaerts valve gear. These parts were meant for upgrading the old MDC/Roundhouse 0-6-0, and I figured there was a chance everything would fit the 2-8-0. I had to shorten some of the valve gear links (lots of careful cutting, filing, and soldering), but otherwise it all worked like it was supposed to.
I made a special retainer plate for the underside of the drivers— two stips of PC board soldered to a brass plate. I soldered wipers made of .002 brass shim to the strips of PC board and bent them so that they contacted the backs of the drivers on both sides.
There were only about a half-dozen good shapshots and one YouTube video on the internet. My friend Cesar had just a few of his own shapshots and memories to go on. I hardly knew what the thing looked like.

"What kind of problem are we looking at, Holmes?"

"Documentary, Watson. Documentary."

But there was one color drawing (below) in a coffee-table train book, "Steam Locomotives," by Cook and Hollingsworth. The only useful dimension was an overall length: 61 ft., 11 in. Well, that's a start.