The Mococo line was upgraded with ties and rail just prior to being removed from service. It's primary use was during the Viet Nam War to move bomb's and ammo to Port Costa. After the war there were several Intermodal trains and a freigt and local that operated over it.
After the removal, it has been used for storage of intermodal, auto and freight cars. One of the problems with this line was the 50 mph crossing signals. In order to bring this line to a high speed rail, they have to change out the rail, up grade the crossing signals and ties. Very expensive at this time.