File:Pennsylvania Railroad - 33164 hopper car 1 (27085227826).jpg

This GL-class hopper car was built by the Pressed Steel Car Company of Chicago, Illinois in October 1898. It was used by the Pennsylvania Railroad until the late 1930s. The car is 35 feet long, weighs 20 tons, and can carry 50 tons of freight.

Info. from museum signage: "Constantly searching for ways to increase payload and reduce maintenance costs, railroads began experimenting with steel car construction in the late Nineteenth Century. Although not the first to build a steep hopper, the Pennsylvania Railroad soon led the way in construction and ownership of such cars. One of the first mass-produced steel hoppers in America, No. 33164 was one of more than 20,000 hopper cars produced for the Pennsylvania Railroad.

The initial problem plaguing the development of steel cars was weight. Because a locomotive is limited to how much weight it can pull, the heavier the cars, the less cargo could be hauled on a single train. Innovations with pressed steel forms made it possible to keep a car relatively light while maintaining the structural integrity of the steel. While this GL car weighs only two tons more than a wooden car built three years earlier, its capacity is increased by ten tons. Larger and stronger cars such as No. 33164 soon led to larger locomotives, longer trains, and heavier rail and bridges.

Built in October of 1898, No. 33164 was part of the initial order of class GL cars placed by the Pennsylvania Railroad. At a time when most railroads were still ordering wooden hoppers, a large order for steel cars such as this was greatly ahead of its time. Wooden cars were used almost exclusively by U.S. railroads until the 1900s, despite several attempts in the 1850s to introduce metal cars. These cars quickly proved their worth, not only by hauling increased payloads, but also by greatly reducing maintenance costs and increasing longevity.