Milwaukee Road class F7
Milwaukee Road class F7
A class F7 being moved out of the Alco factory
|
| Type and origin |
| Power type |
Steam |
| Builder |
American Locomotive Company |
| Serial number |
69064–69069 |
| Build date |
August to September 1938 |
| Total produced |
6 |
|
| Specifications |
| Gauge |
4 ft 8 1⁄2 in (1,435 mm) standard gauge
|
| Leading dia. |
36 in (914 mm) |
|
Driver dia. |
84 in (2,134 mm) |
| Trailing dia. |
38 and 44 in (965 and 1,118 mm) |
| Wheelbase |
Loco & tender: 89 ft 10 in (27.38 m) |
| Length |
100 ft 0 in (30.48 m) |
| Axle load |
72,250 lb (32,770 kilograms; 32.77 metric tons) |
| Adhesive weight |
216,000 lb (98,000 kilograms; 98 metric tons) |
| Loco weight |
415,000 lb (188,000 kilograms; 188 metric tons) |
| Total weight |
791,000 lb (359,000 kilograms; 359 metric tons) full |
| Fuel type |
Coal |
| Fuel capacity |
50,000 lb (23,000 kilograms; 23 metric tons) |
| Water cap |
20,000 US gal (75,700 l; 16,700 imp gal) |
Firebox:
• Firegrate area |
96.5 sq ft (8.97 m2) |
| Boiler pressure |
300 lbf/in2 (2.07 MPa) |
| Heating surface |
4,166 sq ft (387.0 m2) |
Superheater:
|
|
| • Type |
Type E |
| • Heating area |
1,695 sq ft (157.5 m2) |
| Cylinders |
Two, outside |
| Cylinder size |
23 1⁄2 in × 30 in (597 mm × 762 mm) |
|
|
|
| Career |
| Operators |
Milwaukee Road |
| Numbers |
100–105 |
| Retired |
November 1949 to August 1951 |
| Disposition |
All scrapped. |
|
| Type and origin |
| Power type |
Steam |
| Builder |
American Locomotive Company |
| Serial number |
69064–69069 |
| Build date |
August to September 1938 |
| Total produced |
6 |
| Specifications |
| Gauge |
4 ft 8 1⁄2 in (1,435 mm) standard gauge
|
| Leading dia. |
36 in (914 mm) |
|
Driver dia. |
84 in (2,134 mm) |
| Trailing dia. |
38 and 44 in (965 and 1,118 mm) |
| Wheelbase |
Loco & tender: 89 ft 10 in (27.38 m) |
| Length |
100 ft 0 in (30.48 m) |
| Axle load |
72,250 lb (32,770 kilograms; 32.77 metric tons) |
| Adhesive weight |
216,000 lb (98,000 kilograms; 98 metric tons) |
| Loco weight |
415,000 lb (188,000 kilograms; 188 metric tons) |
| Total weight |
791,000 lb (359,000 kilograms; 359 metric tons) full |
| Fuel type |
Coal |
| Fuel capacity |
50,000 lb (23,000 kilograms; 23 metric tons) |
| Water cap |
20,000 US gal (75,700 l; 16,700 imp gal) |
Firebox:
• Firegrate area |
96.5 sq ft (8.97 m2) |
| Boiler pressure |
300 lbf/in2 (2.07 MPa) |
| Heating surface |
4,166 sq ft (387.0 m2) |
Superheater:
|
|
| • Type |
Type E |
| • Heating area |
1,695 sq ft (157.5 m2) |
| Cylinders |
Two, outside |
| Cylinder size |
23 1⁄2 in × 30 in (597 mm × 762 mm) |
| Career |
| Operators |
Milwaukee Road |
| Numbers |
100–105 |
| Retired |
November 1949 to August 1951 |
| Disposition |
All scrapped. |
The Milwaukee Road's class F7 comprised six (#100–#105) high-speed, streamlined 4-6-4 "Baltic" or "Hudson" type steam locomotives built by Alco in 1937–38 to haul the Milwaukee's Hiawatha express passenger trains. Following on from the success of the road's class A 4-4-2s, the F7s allowed the road to haul heavier trains on the popular Chicago–Twin Cities routes.
The F7s are major contenders for the fastest steam locomotives ever built, as they ran at over 100 miles per hour (160 km/h) daily. One run in January 1941 recorded by a reporter for Trains magazine saw 110 miles per hour (180 km/h) achieved twice—in the midst of a heavy snowstorm. Baron Gérard Vuillet, a French railroading expert, once recorded a run between Chicago and Milwaukee where the locomotive reached 125 mph (201 km/h) and sustained an average 120 mph (190 km/h) for 4.5 miles (7.2 km). However, the British locomotive LNER Class A4 4468 Mallard is officially accepted to be the world's fastest, with a run recorded at 126.1 mph (202.9 km/h) in 1938.
The Milwaukee F7s are accepted as the fastest steam locomotives by a different measure—scheduled speed between stations. In 1939, shortly after they were introduced into passenger service, the Twin Cities Hiawatha schedule was modified such that the engines would need to run the 78.3 mi (126.0 km) between Portage and Sparta, Wisconsin in 58 minutes—a start-to-stop average of 81 mph (130 km/h).
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