They pitted the 103 against the most impressive steam power of the day. The results always were the same, as the new diesel-electric proved its superiority time and again. Steam freight schedules were consistently beaten for comparable tonnage hauls.
One of the best “test tracks” was the Baltimore & Ohio’s Cumberland Division, especially its West End. Along that road are several summits, tunnels and 2.2 percent grades. The toughest climb on the division for eastbound coal is an 11.4-mile stretch of 2.2 percent grade from M&K Junction to Terra Alta, W. Va. The B&O typically used a 2-8-8-0 with two 2-8-8-0 helpers at 4590 adjusted tons to run the route. This consist took 80.5 minutes to run the section, averaging 8.4 mph. But when No. 103 left M&K with 1952 adjusted tons, it made the run to Terra Alta in 41.3 minutes -- alone -- and averaging 16.6 mph.
Even though 103 was a freight locomotive, it also made its point in passenger service during the test period. The Northern Pacific, at the end of its tonnage tests, hooked up the diesel units to its trains 1 and 2, the North Coast Limited, between Livingston and Missoula, Mont. This 240-mile stretch of mountain road rose more than 2000 feet in altitude, over 2.2 percent grades. A 4-6-6-4 could handle 10 cars alone, required one helper for 12 cars and two for more than 12 cars. The schedule was 6 hours 30 minutes westbound and 6 hours 38 minutes eastbound. With 103 at the head of a 17-car train, the westbound trip took 6 hours 19 minutes; the eastbound 6 hours 24 minutes.
By the end of the 11-month testing phase, the diesel’s hauling power was uncontested.