The Tehachapi LoopForum staffer Jim Dick posted these notes and photos of the Tehachapi Loop.
We visited the Tehachapi Loop to witness the train traffic that is almost constant.
For those of you that don't know about the Tehachapi Loop, it is an engineering marvel that allows trains to negotiate the Tehachapi Pass. The elevation rise from the valley to the top of the pass is 4000 feet. The section from Caliente to the summit is 2735 feet long. The maximum rise allowed is 2.2%. East of Keene, CA the section requires an 80 feet rise which is more than allowed. William Hood, a civil engineer, solved the problem by creating a loop to allow the track to rise sufficiently in the confined space available. The length of the loop is 3799 feet with a typical diameter of 1210 feet. There is a 77 feet rise in the loop.
With such long trains today it is easy to find trains that will enter the tunnel from the east and cross over itself while traversing the loop. There are approximately 40 trains a day that pass through the loop. We were fortunate to see several during our brief visit. I thought it would be neat to live at Loop Ranch, which is in the center of the loop. After witnessing the first train pass through I decided that, even though I love trains, I would not want to live there. As the train traverses the loop the wheels make un ungodly screeching sound that forced me to turn off my hearing aids! It takes around 5 minutes for a normal train to make the complete loop and pass behind the mountain.
I have included some pictures of a train traversing the loop as well as a panorama of the complete loop taken from the hillside above it. If you like trains this is a stop well worth the time as it is interesting to watch the trains as they head east and west. You can also view other locations as they pass in and out of the many tunnels along the way. There are 18 tunnels for a total of 8240 feet and 8300 degrees of rotation along the complete route.