An engraving of the Prosser steam streetcar, from the August 1888 issue of the Street Railway Journal.
An early attempt at steam motor innovation for streetcars, invented by Treat T. Prosser of Chicago, and after whom it was named. In an era when most steam motors were stand-alone dummy units that hauled passenger trailer cars behind them, the Prosser car looked more like a standard streetcar and could seat passengers on its body. After early trials in St. Paul–Minneapolis, the car came to Portland in June 1889 to with the aim of providing the initial passenger service on the Mount Tabor Street Railway Company’s line on Hawthorne avenue.
The car was given a trial run on June 21, 1889 and seems to have performed satisfactorily at first. However, later articles reveal that the car’s motor could not reliably provide enough power to propel it up hills. Some effort was made to fix the problem — a July 12, 1889 article notes that “some changes have had to be made in the motor” — but by late July, a new order had been made with the Baldwin Locomotive Works for a standard steam dummy to replace the failed Prosser car. This new motor arrived in Portland on August 13, 1889 and was ready in time for the opening of the Hawthorne avenue line in early September. The Prosser car sat abandoned at the outer end of the line for at least four years, seen merely as a “curious relic.”