Olive Dennis (1885 - 1957) was an American engineer whose design innovations changed the nature of railway travel. She studied civil engineering at Cornell University. In 1920, she was hired as a draftsman by the B & O Railroad to design bridges, then Daniel Willard, Railroad President, observed that, since half of the railway's passengers were women, the task of engineering upgrades in service would best be handled by a female engineer, so Dennis became the first "service engineer".

She introduced seats that could partially recline; stain-resistant upholstery; larger dressing rooms for women, with free paper towels, liquid soap and drinking cups; ceiling lights that could be dimmed at night; individual window vents for fresh air while trapping dust; and air conditioned compartments. She later designed an entire train, the Cincinnatian, that incorporated all of her innovations, "the crowning glory of her career". She joined  WES in 1931. "No matter how successful a business may seem to be," she said, "it can gain even greater success if it gives consideration to the  woman's viewpoint."