Don Ball's HO Stockton & Copperopolis RR— California's Gold Rush Country in 1895
Bernard Kempinski's O scale Aquia Line— American Civil War models
Craig Bisgeier's HO Housatonic Railroad— Connecticut and the Northeast in 1892
Dan D. Sparks' HO San Diego Electric Railway— turn-of-the-1900s in sunny Southern California
CW Railman's California Western Locomotive & Rebuild Shops— HO projects and thorough how-tos
Thom Radice's HO Western & Atlantic RR— American Civil War
Mike Hohn's HO Southern Central Railroad, upstate New York in 1888
Eric Hansmann's blog, HO how-tos and what-happens over a wide range of topics
Layout tours, including George Sellios' HO Franklin & South Manchester
Layout tours and modeling portfolios slow-loading site but worth it!
VITAL VENDORS— HO old-time specialists
Amesville Shops— limited-run period HO car kits in resin and laser-cut wood
BEST—Bollinger Edgerly Scale Trains— prototype-accurate period craftsman HO structure kits
Bitter Creek Models— HO old-time car kits, detail parts, and the best selection of 19th-century trucks imaginable
B.T.S.— HO craftsman car kits and structure kits for the American Civil War era, plus structure kits in all scales
Classic Miniatures— an old favorite supplier of HO western structure kits
Clover House— another old favorite for old-time freight car dry transfers, PC board tie strips
Comstock Carshops— old-time HO western structure kits and detail parts
Eight Wheeler Models— the best limited-run HO craftsman car kits— also check out Eight Wheeler Models' Shapeways shop for great parts, trucks— and hats to backdate your HO population.
Rio Grande Models— HO metal castings, car kits, HOn3 trucks— mining, logging, industrial, old west models
Rusty Stumps— HO craftsman structure kits and laser-cut detail parts
Silver Crash Car Works— outstanding limited-run HO resin car kits (Site is occasionally on hiatus)
SMR Trains— amazing O scale 19th century locomotives and cars, well worth a look
Train Troll— craftsman HO ships and watercraft
Trout Creek Engineering— an old favorite supplier of HO wood car kits
PLEASE NOTE— THIS IS NOT AN INCLUSIVE LIST! Given the sad state of my memory and organizational ability, I've probably left out many important people, vendors, and websites. I encourage viewers to click around in others' link lists and explore on their own. There's lots of good modeling out there.

Almost all the vendors on the list are very small one-and-two-person operations with limited time, resources, and abilities to handle special customers. PLEASE deal with them with patience and respect.

Andrew Stadden— the very best late-Victorian/Edwardian pewter figures in HO and OO
Blue Moon— 15 mm old west figures, slightly short for HO
Fun & Games— carries a lot of the older HO old-time cast metal figures from Lytler & Lytler and others

150 (or so) Mostly 1850s American Standard 4-4-0 Locomotives: Drawings and Lithographs Scaled for HO— 60 pages of PDF documents

Download Part 1: HO drawings

Download Part 2: color lithographs

Scans and scaled drawings, plus reproductions of colored lithographs, from a variety of books and online sources, all scaled (best as I can figure) to 1/87. (Beware: big 30-meg files, slow download.)

Last update in November, 2016

Adobe Photoshop and Illustrator Guide for making art for printed car sides—
2-page PDF document

How to use old photos as templates and reproduce the car paint and lettering. The techniques are also useful for different kinds of photo-manipulation and vector-based illustration software. Click on the head or image for a download.

Jackson & Sharp railroad car photos in the Delaware Heritage Collection. Dozens of 19th century builders' photos from one of the largest passenger car builders. Search for "railroad."
Harrisburg Car Mfg. Co. photographs at the University of Pennsylvania Library website. Outstanding collection of freight car photos from the 1870s and 1880s.
The William Halsey Locomotive Drawing Collection at the Southern Methodist University (DeGolyer Library) website. The most important reference for engine painting and decorating in the 1860s and 1870s— hand-painted side views of dozens of Erie RR engines.
Mid-Continent Railway Museum— amazing collection of restored late 1800s–early 1900s railroad cars, plus background information on the major carbuilders.— Indispensable website stuffed with nowhere-else information— Historical Data section on locomotive and car builders, locomotive painting, structure painting, Russia iron, links to period texts— too much to summarize.
St. Charles Car Company photos at the St. Charles City-County Library website. Another great collection of 19th-century car photos.— history, specifications, and photos of the Virgina & Truckee's rolling stock plus magnificent color artwork of the line's locomotives.
The Original Whistle Stop is Los Angeles' best train store— best I've been in anywhere from Burbank to Boston. Fred Hill and his team have been keeping my trains running and workbench stocked for 40 years— if anybody deserves a plug, it's them.
Art Griffin Decals— huge selection of period HO freight car and wagon decals, plus car kits and prototype photoprints (Site is sometimes on hiatus)
Bar Mills Scale Model Works— Creative laser-cut craftsman structure kits with a New England flavor, in all scales
Gerry Dykstra's Shapeways Shop— 3D printed engine parts to build two outstanding HO models of Civil War engines— parts great for free-lancers and scratch-builders too.
Alan Mueller's books— If you want to craft your own mid-19th century locomotive, there are no finer how-to resources. Al Mueller walks you through step-by-step processes to modify Mantua Generals or start from 3D printed parts. The processes learned in these books will improve your model-building— no matter what prototypes you choose.