Olean was the railroad and pipeline hub for the surrounding oil region. The operations HQ of Standard Oil's New York affiliate, Socony, was based in the city. Oil produced on both sides of the state line (e.g. in Bradford, Pennsylvania) would be transported to Olean for rail travel. For a short time, Olean was the world's largest oil depot, complete with a "tank city" on the edge of town. A pipeline was also built linking the city to Standard Oil refineries in Bayonne, New Jersey. The oil industry maintained a presence in the city until 1954, the same year in which Olean's population peaked.