By the late 1950s, commuter service had become a drag on profitability for the PRR and Reading, like most railroads of the era. Commuter service requires large amounts of equipment, large numbers of employees to operate equipment and station sites, and large amounts of maintenance on track that see extremely heavy usage for only six hours a day, five days a week. Meanwhile, the rise in automobile ownership and the building of the Interstate Highway System chipped away at the steady patronage as population in the suburbs grew. When the Philadelphia suburbs were small towns, people lived close enough to a train station to walk to and from the trains. When the suburbs expanded into what had been fields and pastures, the trip to the station required an automobile, leading commuters to remain in their cars and drive all the way into the city as a matter of convenience.