The 2-2-2 wheel arrangement was a natural progression from the 0-2-2
and the 2-2-0 arrangements. The additional axle of the 2-2-2 provided
more stability and allowed the locomotive to have a larger firebox.
It was first found on the Patentee locomotive built by Robert Stephenson
and Company in 1833. Locomotives of this wheel arrangement was sometimes
called "Singles" because they had a single driven axle (which could also
be said of the various other single driven axle wheel arrangements).
| No. | Class | F.M. Whyte | Gauge | Railroad Line | Location | Status | Builder Information | Notes |
|---|
| 13 | | 2-2-2T | 4'-8½" | CVRR |  B&O Railroad Museum, Baltimore, MD | display | Seth Wilmarth, 1851 |  Named Pioneer. On loan from the Smithsonian Museum  |
| | 2-2-2T | 4'-8½" | Reading | Museum of Transportation, St. Louis, MO | display | Baldwin #10174, 05/1889 | Named Black Diamond |
| | 2-2-2T | | | a few miles offshore, Asbury Park, NJ | sunk | 1850 | |
| | 2-2-2T | | | a few miles offshore, Asbury Park, NJ | sunk | 1850 | |
| | 2-2-2 | 4'-8½" | | Canadian Railway Museum, Delson, QC | operational | | Named John Molson, replica |