What did Paul L. Downing invent?

According to The Black Inventor Online Museum, Phillip L. Downing invented the mailbox. Prior to Downing's creation of the four-legged metal mailbox, those wanting to mail a letter had to make a long trip to the nearest post office.

Downing patented his mailbox on Oct. 27, 1891, and called his invention a "street letter box." One year prior to inventing the mailbox, Downing patented an electrical switch that allowed railroad workers to turn on or off the power supply to trains at the necessary times. Downing's designs for the railroad switch were used as inspiration for inventors who created residential electrical switches.