Los Angeles transportation history is littered with lost rail lines, but this one is especially wild: there were Red Car trolley tracks running down the center of the 101 Freeway's ancestor through the Cahuenga Pass. The Metro Transportation Library shares this photo and Nathan Masters explains at Los Angeles mag: "when Mayor Fletcher Bowron, actor Gene Autry, and other dignitaries dedicated the Cahuenga Pass Freeway on June 15, 1940, its two frontage roads and eight concrete lanes were divided by two sets of trolley tracks." Buses replaced rail on the San Fernando Valley line at the end of 1952, and eventually the median was paved over for, you guessed it, more car lanes. Today the Red Line subway goes through the Cahuenga Pass (with much worse views) and the Green Line light rail runs down the median of the 105 Freeway for a while (also worse views).
· CityDig: When Trolley Tracks Divided the 101 [Los Angeles]