The Milwaukee Road's class F7 streamlined steam locomotive. Milwaukee Road Photo.
The Milwaukee Road Class F7 Streamlined Steam Locomotive
The Milwaukee Road's class F7 comprised six (No. 100 – No. 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 4-4-2's, the F7's 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 daily. One run in January 1941 recorded by a reporter for Trains magazine saw 110 miles per hour 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 and sustained an average 120 mph for 4.5 miles. However, the British locomotive LNER Class A4 4468 Mallard is officially accepted to be the world's fastest, with a run recorded at 125.88 mph in 1938.
The Milwaukee F7's 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 between Portage and Sparta, Wisconsin in 58 minutes—a start-to-stop average of 81 mph.
First-built No. 100 was also the first withdrawn from service, on November 10, 1949; last-built No. 105 was the final one in service, withdrawn August 10, 1951. Sadly, all were scrapped.
A Milwaukee Road Class F7 Slideshow.
Milwaukee Road Number: 101
Milwaukee Road Number: 102
Milwaukee Road Number: 103
Milwaukee Road Number: 104
Milwaukee Road Number: 105
Type and origin
Power type: Steam
Builder: American Locomotive Company
Serial numbers: 69064–69069
Build date: August to September 1938
Total produced: 6
Gauge 4 ft 8 1⁄2 in standard gauge
Leading wheel diameter: 36 in
Driver diameter: 84 in
Trailing wheel diameter: 38 and 44 in
Wheelbase Loco & tender: 89 ft 10 in
Length: 100 ft 0 in
Axle load: 72,250 lb
Weight on drivers: 216,000 lb
Locomotive weight: 415,000 lb
Locomotive and tender combined weight: 791,000 lb
Fuel type: Coal
Fuel capacity: 50,000 lb
Water capacity: 20,000 US gal
Boiler pressure: 300 lbf/in2
Firegrate area: 96.5 sq ft
Heating surface: Total 4,166 sq ft
Superheater type: Type E
Superheater area: 1,695 sq ft
Cylinders: Two, outside
Cylinder size: 23 1⁄2 in × 30 in
Tractive effort: 50,294 lbf
Factor of adhesion: 4.29
Operator: Milwaukee Road
Retired: November 1949 to August 1951
Disposition: All scrapped.
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Text: wikipedia.org. Images: Public Domain; http://www.commons.wikimedia.org (unless otherwise specified) and 17 U.S. Code § 107 fair use. References: Lewis, Robert G. The Handbook of American Railroads. New York: Simmons-Boardman Publishing Corporation, 1951, 2nd Edition 1956. Site Map Contact webmaster HERE.