[3] In 1920, she became only the second woman to obtain a Civil Engineering degree from Cornell [disputed – discuss].

She was hired that year as a draftsman by the B & O Railroad to design bridges, the first of which was in Painesville, Ohio.

This train, the Cincinnatian, was deemed "the crowning glory of her career" by historian Sharon Harwood.

[6] Among the innovations that Ms. Dennis introduced on passenger trains were seats that could partially recline; stain-resistant upholstery in passenger cars; larger dressing rooms for women, supplied with free paper towels, liquid soap and drinking cups; ceiling lights that could be dimmed at night; individual window vents (which she patented) to allow passengers to bring in fresh air while trapping dust; and, later, air conditioned compartments.

Other rail carriers followed suit in the years that followed, and buses and airlines, in turn, had to upgrade their level of comfort in order to compete with the railroads.