Amongst a trip to LA to visit family, I made a commitment to find and photograph the "famous" Beale's Cut (that no one I've talked to so far has heard of before me). I bought the Ridge Route book, because I am fascinated with this sort of history.
Looking north up Beale's Cut, earliest known photo. Taken from here.
By 1910, traffic had significantly changed... from the horses and carriages that scrambled up and over the cut in the late 1800s to motor vehicles (the allegedly had to drive up the cut in reverse so that fuel reached the engine), to cargo trucks in the early 1900s. As a result, the Newhall Tunnel was constructed for truck traffic nearby, actually tunneling through the mountains, and the Cut was essentially abandonned. Traffic though (again, depending on which source you read) still used it until the original construction of Ridge Route in 1915.
Depending on which source you read, the cut collapsed sometime in the late 1930's, losing 2/3 of its depth. Below is the photo that I took with my phone (why oh why did I forget my camera???), at approximately the same angle as the B&W photo above. It's obviously overgrown.
The Cut was used for backdrops (either superimposed or actually filmed there) for Westerns. There is also apparently a famous (but superimposed) photo of some Western star jumping on a horse across the cut. Look it up on google if you want.
This is an aerial photo looking south with the Cut in the middle. Hwy 14 is to the left.
Cool stuff I say. Cool stuff.