I have a video, produced by The History Channel, detailing the planning and construction of Penn Station in New York City. Penn Station was completed and opened in 1910 I believe. In that video, a railroad historian claims that Pennsylvania railroad was by far the largest and richest of all the railroads of that time. Did that change over the years? I have the impression that in the 1940's there was nothing larger than the mighty New York Central.
Fierce rivals before their merger, PRR was always bigger than NYC by any measure.
Here's part of a Wikipedia entry:
"The PRR was the largest railroad by traffic and revenue in the U.S. throughout the first two-thirds of the twentieth century and was at one time the largest publicly traded corporation in the world. At its peak, it controlled about 10,000 miles (16,000 km) of rail line. During its history, the PRR merged with or had an interest in at least 800 other rail lines and companies. The corporation still holds the record for the longest continuous dividend history: it paid out annual dividends to shareholders for more than 100 years in a row. At one point the budget for the PRR was larger than that of the U.S. government; at its peak it employed about 250,000 workers."