The Goat Canyon Railroad Trestle Anza Borrego. Distance: 4-6 miles. Hidden back in the desert mountains of Anza-Borrego State Park east of San Diego is the largest wooden railroad trestle in the world. This trek is not for the inexperienced hiker and will most likely take you a whole day. The "trail" is not marked or maintained and is pretty much non-existent. You’ll have to do some navigating for this one.