If you go over the summer then Chama is the place to be. They will have all their 5 k36s, the 463 (a K27), four k37s on display, as well as the Ten Wheeler 168. Durango Railwoad historical society has their 315 and hopefully others like the Eureeka and Glenbrook will be there for the 50th anniversary. Alamosa also has 169 the sister to the one mentioned before though it is not operational. Durango has 3 K28s, 4 K36s and a newly restored k37 493 as well as Rio Grande Southern Consolidation 42. Heading north you have Gallopinf Goose 5 in Dolores, 4 in Telluride, and Motor Car 1 and Model T Inspection Car in Ridgeway (though these are railbuses). Locomotive 268 is in Gunnison as we as 276 is on a bridge in Cimarron. 499 is at Royal Gorge Park with West Side Lumber 8 at the depot in Cañon city. Heading further north at the Colorado Railroad Museum in Golden they have the last Standard Gauge Rio Grande steamer 638. They also have West side lumber 14 and 12 with Rio Grande 318, 491, and 364. They have Rio Grande Southern number 20 and Colorado and southern 74 (though it is painted as Colorado and Northern 30). They lastly also have a Burlington Route 4-8-4 Northern (my favorite of all). In Idaho Springs the have C&S 60 and in Breckenridge the have C&S 9. Leadville has the last Standard Guage Steam locomotive in commercial revenue service in the US, a consolidation though I can’t remember it’s number. Black Hawk has Ferrocales y Zacatecas 12 but it is labeled Colorado Central 71 and it was never used on any railroads in the US. Central City in turn has C&S 71. Georgetown Loop has IRCA locomotives 40, 44, and 111 from El Salvador and Guatemala as well as 12 from Hawaii. Lastly there is a Big Boy in Denver and hopefully 4014 will be visiting for you to see (a restored Big Boy). Feel free to add any I missed