Los Angeles Railway PCC car No. 3020 crosses the 1st Street Bridge outbound on the P Line 1938

1938, Los Angeles Railway PCC car No. 3020 crosses the 1st Street Bridge outbound on the P Line, Los Angeles, CA.

1956, Thank you to Wikipedia for this pic of the Rimpau Loop Terminus.

In the 1920 service rerouting, the western end of the West Pico and Santa Fe Station Line was combined with the eastern portion of the Boyle Heights and West 7th Street Line to form the West Pico & East First Street Line.  The new line ran from Brooklyn and Rowan via Rowan, First, Broadway, and Pico to Delaware. It was assigned the letter designation P in 1921. While the route was unchanged for the rest of its existence, the Rimpau Loop and Dozier loop were added in 1935 and 1936, respectively.