Railroads in World War II would greatly need the new diesel locomotives being produced by Electro-Motive Corporation (later EMD) beginning in the 1930s, as the U.S. needed to move hundreds of tons of goods, material and troops to fight against Germany and the Axis after it was bombed by the Japanese in December of 1941. This time, however, railroads were prepared for the onslaught of new traffic and no government oversight was needed during the conflict. Not only did railroads see record freight traffic during the war years but also the industry witnessed a passenger renaissance as folk returned to the rails, partly due to the new streamliner concept and partly because the government needed the trains to move large numbers of troops. In any event, without the railroads World War II certainly could not have been won by the Allies.
When compared to what happened during World War I, railroads in World War II were phenomenally more efficient. Not only did they move more tons of material and goods during the second conflict but railroads also did so with fewer locomotives, cars, and overall rail mileage. By the end of World War II there was only 226,000 miles of track while at the beginning of World War I the industry had over 254,000. It should be noted that railroads did have improved technology to move freight in the 1940s such as heavier freight cars and locomotives and the new diesel-electric locomotive. However, the accomplishments they were able to achieve from the first conflict are still impressive.
Another new technology that helped railroads during the decade was the development of Centralized Traffic Control, or CTC. CTC gave a dispatcher complete control over a section of track, known as a block, to set switches and watch over signals. The new system allowed for a single track main line to achieve 75% capacity of a fully double-tracked line. CTC was originally implemented in 1927 but with the help of the government hundreds of miles of additional main line were covered with system allowing for much more efficient railroad operations.
What's more the war years saw the railroad industry's overall operating ratio drop to a record low of 67.5% while profits were so lucrative that, overall, lines were able to repay $2 billion in debt. Perhaps it was the government that gained the most from the industry's efficient operations during World War II. Because of the land grant discounts that still applied to western lines the fed saved approximately $900 million. Following the war, however, Congress ended the discount.
The 1940s also saw the peak of piston-driven steam locomotive technology. Because of wartime restrictions the government did not allow the building of new diesel locomotives because the steel and other metal components required was needed for the war effort. Instead, railroads were forced to buy steam locomotives to fill their motive power needs. Thus, for instance, the Baltimore & Ohio purchased its newest and last steam locomotives in the early 1940s of the 2-8-8-4 Yellowstone Type.
Designated the EM-1 Class by the B&O it had a rather low boiler pressure comparative to other models in its class but this low pressure had a great benefit, a high factor of adhesion (4.22). This high ratio allowed the locomotive to start rather efficiently in that it was not as susceptible to wheel slippage as other designs. For instance, this added incentive was an extra benefit in the type of service the B&O originally designated the EM-1, the torturous grades of the railroad’s West End (its Cumberland Division), through the Appalachians. The locomotive did a marvelous job at this, having little trouble hauling merchandise or coal drags over the steep climbs of Cranberry Grade, along the West Virginia/Maryland border, or over Sand Patch in Pennsylvania.
Railroads slowed their pace of christening new streamliners in the 1940s to concentrate on winning the war, although train travel remained a popular mode of transportation for most during the decade. However, following World War II and into the 1950s railroads watched helplessly as passenger traffic plummeted and not even new equipment and promotional advertising could sway passengers back to the rails. Some lines continued to spend money on new streamliners, such as the Pennsylvania Railroad, for passengers that never came. The 1950s also saw a slow decline in freight traffic as the new interstate highway system began to take its toll.