The Metro A-Line runs from downtown Los Angeles to downtown Long Beach, and about 90% of it's route is along the old Pacific Electric right of way, which ran from 1902 until (under the yesteryear LAMTA) it was discontinued in April 1961.
Here's a circa 1996 set of Los Angeles County Metropolitan Transportation Authority's Blue Line (now A-Line) trains at Imperial Highway. The train on the left is outbound toward Long Beach, and the one on the right is inbound to Los Angeles.
This scene has changed since this photo was taken. There is now an elevated bridge over these tracks for automobile traffic. The MTA shares right-of-way at this point with the Union Pacific (absorbed the Southern Pacific who originally used these tracks in conjunction with PE).
The UP, like SP when it operated here, has a nasty habit of running mile long trains that choke auto traffic as they pass through (particularly when they run out of time on the federal time limit, and simply "park" the train, blocking intersections for blocks!)
Chris Carson photo