The majority of files within this series consist of court hearings before the Interstate Commerce Commission related to rates on various freight commodities, tax cases, and other issues such as passenger fares. The rate cases apply to lines ranging from the Southwest, New England, Midwest, and Mid-Atlantic, and include, among others, cases involving the Lehigh Valley RR and the Baltimore & Ohio, Langdon’s employers for much of the 1930s. Along with the Lehigh Valley and B&O hearings, Langdon served as general counsel in most of the other cases within the series.

Subseries B contains numerous House, Senate, and ICC hearings focusing on competitive shipping rates throughout the transportation industry with a particular emphasis on trucking and water rates. There are also several reports and studies detailing the effects of fluctuating railroad freight rates on other industries. Moreover, the subseries includes analysis on the effects of ICC regulations and the impact of new technologies and energy sources on railroads. Subseries C includes numerous speeches given by Langdon and other railroad executives cover subjects such as their opposition to competitive rate rules, general railroad operations, and the need for less restrictive regulations on railroads and other freight carriers.