Locomotives of the old west - Model Railroader Magazine

Historically, the "Old West" out here as far as railroading goes, begins about 1863 with the first shovelful of dirt here in Sacramento on the Central Pacific, and ends about 1910 or so.  So you'd have a pretty good group of locomotives to model.  

4-4-0's of course, though out here in the West, 4-6-0's were a little more popular, since they were heavier and could act as both passenger and freight power.  Central Pacific (and the later Southern Pacific) had a pretty sizeable fleet of both 2-8-0 and 4-8-0 freight power from about 1880 on, and even a 4-10-0, the "El Goberanodor", though it wasn't that successfull--not from steaming problems as much as finding a turntable long enough to turn it on.  

Great Northern was fond of the 4-8-0 wheel arrangement in the Cascades, and Northern Pacific even had a pair of 2-10-0's crossing the switchbacks of their Cascade route before the Stampede Tunnel was built.  And both railroads embraced the 2-8-0 as quickly as they could get them.   And the 2-8-0 was very quick to gain acceptance on the Rio Grande in both standard and narrow-guage versions.   

Railroads out here in the Wild West had to contend with grades far steeper and curves far more numerous than a lot of railroads Down East, so the 4-4-0 was pretty much limited to the more level stretches of the terrain and not nearly as numerous or useful out here as were the heavier locomotives of the 2-6-0, 4-6-0, 2-8-0 or 4-8-0 arrangement.   And yes, a Diamond-stack 2-10-0 wasn't really an Odd Duck out here, either.    

Though not a general rule, the heavier and more powerful locos from Baldwin and Alco were gobbled up out here as fast as they came out of the plants.  SP had the first 2-8-8-2's running before 1910.   Both 4-8-2, 2-8-2 and 4-6-2 wheel arrangements were 'out west' almost as soon as they came out of the plants in the East, and well before the 1917 USRA designations.

So if your "Old West" layout is planned anywhere from about 1863 to about 1910, you've got a lot of locos you can count on.  They weren't all baloon-stacked 'Tea-kettles'.  Not by a long shot. 

Tom