The Pennsylvania Railroad—or PRR, or Pennsy, as it was variously called—was one of two dominant eastern-United States rail franchises for most of the 20th century. The other was the New York Central, which merged with the Pennsy in 1968 to form Penn Central.

The PRR was founded back in 1846 to transport people and freight between Harrisburg and Pittsburgh, Pennsylvania. That line opened in 1854. The railroad quickly expanded, and by 1887, the Pennsy had introduced the first passenger cars with vestibules at either end. These fully enclosed trains ran between New York City and Chicago. Actually, the road’s eastern terminus ended at Jersey City, New Jersey, but the railroad extended its reach into Manhattan proper in 1910 when it completed Penn Station on 34th Street.

One of the many things model railroaders like about the Pennsy is its relationship in the 1930s with industrial designer Raymond Loewy. When Loewy signed on to design locomotives and cars for the railroad in 1934, the PRR was at its height, with 100,000 employees serving half the country’s population...