Will fan factor work for or against Rangers?

How big a factor will the Ibrox crowd be in Sunday's Old Firm showdown?With no away fans in attendance, Rangers will be backed by 50,000 supporters in the League Cup last-eight tie against Celtic.But that could turn out to be a help or a hindrance.Speaking on the BBC's Scottish football podcast, Ewan Murray - The Guardian's Scottish football correspondent - explains: "The 50,000 Rangers fans element is interesting because Ibrox for a home player can be a difficult place to play when things are n