Graphic designer Emily Sneddon performed some impressive typographic anthropology to digitize the font used on San Francisco’s MUNI light rail cars. She tracked down the original engineer who worked on the destination display signs for a company called Trans-Lite.

Sneddon, on her blog:

Learning that the alphabet came from an engineer really explains its temperament and why I was drawn to it in the first place. The signs were designed for sufficiency: fixed segments, fixed grid, and no extras. Characters were created only as destinations required them, while other characters, like the Q, X, and much of the punctuation, were never programmed into the signs. In reducing everything to its bare essentials, somehow character emerged, and it’s what inspired me to design Fran Sans.