SP,
I work in the intermodal industry and haven't heard anything about it, however, I'm not sure that I would unless the it affected UP's routing or pricing in that lane. As it stands right now, the main line splits at Reno and one line goes north throught Portola, Keddie and Oroville, and the other heads south.
After you brought it up, I have noticied that everytime I track my containers, once they hit Reno they go through Portola etc... I've never seen one go on the southern line, unless there is no tracking devices between Reno and Roseville (which is possible.)
As far as the routing on the Northern vs Southern routes, I would have to say it depends on the origin & destination of the shipment. If you're shipping from the East Coast to N. California (Oakland, Fresno etc) they are probably going to interchange in Memphis or Chicago and head over the northern route.
If you're shipping from the East coast headed to the LA basin, again, you'll interchange in Memphis or Chicago and then take the Southern route.
Overall, it might appear (and there probably is) more volume on the southern route, but I would attribute that to the LA and Long Beach ports. I am just specualting here about volume though.
DBD