The preload shift pays the highest currently (if you load the package cars). Supposedly something was going to be done to get the 9.50 for the whole shift, but I don't know the progress on that (in the NE anyway).
Other than that if you get on a hub sort, the sort isle pays the most as it is a skilled position. You have to pass a sort test in some hubs, others just put you there from what I hear on here. Either way you'll be making 9.50 with better hours than preload (if you get on the twi or day shift). You get a raise after 90 days, I don't know if the new progression is in effect for new hires (1.00 after 90 days instead of 50 cents). Hopefully a contract guru can lend a hand here.