Yes, and Pittsburgh too ! Pgh had the most of any city and kept none ! There is a stationary PCC in the Heinz History Center and one that runs(I think) at the trolley museum near Washington, Pa. The PCCs ran forever and they have bought replacements for them several times over.
Yes indeed we had the most PCC cars in service in the USA in Pittsburgh for many years but unfortunately not the most ever of any US city. Before we hear from a Chicago member we were second to Chicago who had purchased just 17 more PCC cars than our total fleet of 666 PCC cars. However, the Chicago PCC streetcars had a relatively short career because in 1947 as their last order of PCC cars was arriving the decision was made to start replacing trolley lines with busses! It took 11 years to complete the conversion as the last Chicago PCC streetcar was taken out of service in 1958. Some of the newest PCC cars which were purchased early in 1947 barely had 10 years of operating time. OTOH, essentially all of Pittsburgh’s 666 PCC’s were still in service in 1958 (notable exceptions were the 14 PCC’s destroyed by fire at the Homewood Car Barn in 1955). So it’s safe to say we had the largest operating PCC fleet system in the USA from 1958 and many years thereafter.
Across the border in Canada, Toronto had more PCC’s than Pittsburgh or Chicago with 745 although they bought 205 of them used from Birmingham, Cincinnati, Cleveland & Kansas City when those cities abandoned streetcars.
That surviving car at the Pennsylvania Trolley Museum in “Little Washington” you mentioned is Pittsburgh Railways #1711 which is operational and there are also 3 other Pittsburgh PCC’s at the Museum including the last PCC to operate in revenue service in Pittsburgh in 1999 - PAT car #4004 which was a rebuilt 1700-series PCC, and it is also in operating condition. There are, or were, 2 other static Pittsburgh PCC cars sitting outdoors that I know of, one in Bethel Park and one at the PAT South Hills Village Station near the Mall.
And in response to Mitch’s posting, there are two former PTC/SEPTA PCC’s at the Museum, one of which is operational as seen in the attached photo with yours truly at the controls in 2011.