RailGiants in Pomona is especially rewarding for visitors interested in the engineering variety hidden behind the familiar appearance of a steam locomotive. The collection preserves Southern Pacific No.5021 and Union Pacific No.9000, both examples of three-cylinder steam design. The museum identifies them as two of only four surviving three-cylinder steam locomotives, giving the collection a significance beyond the impressive size of the engines themselves.
A third cylinder represents a different approach to producing power from steam, compared with the two-cylinder arrangement many visitors associate with an American locomotive. Looking at these machines encourages questions about how engineers tried to balance power, mechanical complexity and practical maintenance. Their survival allows competing solutions to the same railway problem to be compared in full size rather than only through technical drawings.
The collection also provides contrasts in scale and purpose. Other equipment associated with Southern California railway history includes smaller locomotives and cars, showing that the railroad world was not made up entirely of enormous mainline engines. A narrow-gauge industrial locomotive, for example, represents a very different working environment from a giant freight engine. The most interesting visit moves between those differences instead of treating every exhibit simply as another old train.
RailGiants is maintained by the Southern California Chapter of the Railway & Locomotive Historical Society. The parent society dates to 1921 and has long promoted historical research, documentation and preservation. That identity helps explain the museum’s emphasis on particular machines and their technical significance. Volunteer work keeps the collection available for public interpretation and supports the continuing care of equipment that can no longer rely on a railroad’s operating budget.
The museum is located inside the Los Angeles County fairgrounds, so visiting arrangements differ from a museum with unrestricted daily access from a public street. Open houses, fair dates and special events provide public opportunities, and advance arrangements may be possible for some groups. Once there, compare the engineering details of the two three-cylinder engines and look for the less obvious equipment that broadens the story beyond sheer locomotive size.
Visitor information
Researched November 2026.
Sources
More railroad museums in California
- California State Railroad Museum — Sacramento: Major railroad museum
- Fullerton Train Museum — Fullerton: Passenger-car and railroad collection
- Golden Gate Railroad Museum — Schellville: Locomotive and passenger-equipment preservation collection
- Laws Railroad Museum — Bishop: Railroad and local history museum
- Lomita Railroad Museum — Lomita: Railroad museum
- Nevada County Narrow Gauge Railroad Museum — Nevada City: Narrow-gauge railroad museum
- Niles Canyon Railway / Pacific Locomotive Association — Sunol: Operating railroad preservation collection
- Niles Depot Museum — Fremont: Depot and railroad history museum
- All 19 railroad museums and sites in California
Keep exploring
- All heritage sites — museums, stations and landmarks
- Pacific — the trains you can ride in the region