One thing that might help is to realize that there are three tracks at Cumbres as the "Y" is not on the main line but rather on a siding off the main. Although not long, this "parallel" leg of the wye could hold perhaps eight of ten cars and I have seen pictures of cars spotted there. As I remember also there is a crossover between the house track and the main east of the station location although I don't think it is currently connected (got to look that one up in my records).
All this makes possible to get "around" trains at the top.
Frank