2-8-8-4 "Yellowstone" Locomotives in the USA
Only 72 Yellowstones were built (in five different classes). Each class of Yellowstone was a different design (except for the two classes owned by the DM&IR). The design was usually dictated by the specific needs of the railroad that received them. The first to have a Yellowstone built was the Northern Pacific who named the wheel arrangment after Yellowstone Park (a region serviced by the Northern Pacific).
| Railroad | Class | Quantity | Year Built | Builder |
|---|---|---|---|---|
| NP | Z-5 | 12 | 1928 | ALCO(1), Baldwin(11) |
| SP | AC-9 | 12 | 1939 | Lima |
| DM&IR | M-3/4 | 18 | 1941 | Baldwin |
| B&O | EM-1 | 30 | 1944 | Baldwin |
A Comparison of Yellowstone Designs
This table compares the various Yellowstone designs along with that of the UP Big Boy and Western Pacific 2-8-8-2. All Yellowstone classes employed simple steam expansion and thus none can be called "mallets".
| Type | NP Z-5 | SP AC-9 | DM&IR M-3 | DM&IR M-4 | B&O EM-1 | UP 4884-1 | WP M-137/151 |
|---|---|---|---|---|---|---|---|
| Series | 5000 | 3800-3811 | 220-237 | 228-237 | 7600-7619 | 4000-4019 | 251-260 |
| Cyl:dia x stroke | 26x32 | 24x32 | 26x32 | 26x32 | 24x32 | 23.75x32 | 26x32 |
| Driver diameter | 63 | 63.5 | 63 | 63 | 64 | 68 | 63 |
| Boiler pressure | 250 | 250 | 240 | 240 | 235 | 300 | 250 |
| Grate area | 182 | 139.3 | 125 | 125 | 117.5 | 150 | 145 |
| Evaporative heating surface | 7673 | 6918 | 6780 | 6758/6780 | 5298 | 5889 | |
| Superheater heating surface | 3219 | 2831 | 2770 | 2770 | 2118 | 2466 | |
| Weight on drivers | 554,000 | 531,200 | 560,257 | 564,974 | 485,000 | 540,000 | 552,700 |
| Total engine weight | 715,000 | 689,900 | 695,040 | 699,700 | 628,700 | 762,000 | 665,100 |
| Tender weight | 401,000 | 400,700 | 436,635 | 438,335 | 382,000 | 427,500 | 408,250 |
| Tractive force engine | 145,930 | 124,300 | 140,000 | 140,000 | 115,000 | 135,375 | 137,000 |
| Tractive force booster | 13,400 | None | None | None | None | None | 13,900 |
Railroads that used 2-8-8-4 "Yellowstone" Locomotives in the USA (data provided by Steve Llanso of Sweat House Media)
Surviving Examples of 2-8-8-4 "Yellowstone" Locomotives in the USA
| No. | Class | F.M. Whyte | Gauge | Railroad Line | Location | Status | Builder Info | Notes |
|---|---|---|---|---|---|---|---|---|
| 2-8-8-4 | 14½" | Whiskey River | unknown, Cleveland, OH | stored | From Marshall, WI; being regauged to 16. | |||
| 227 | M-3 | 2-8-8-4 | 4'-8½" | DM&IR | Lake Superior Railroad Museum, Duluth, MN | display | Baldwin #62533, 1941 | |
| 225 | M-3 | 2-8-8-4 | 4'-8½" | DM&IR | US 2, Proctor, MN | display | Baldwin #62531, 1941 | |
| 229 | M-4 | 2-8-8-4 | 4'-8½" | DM&IR | D&IR Depot, Two Harbors, MN | display | Baldwin #64708, 1943 |
