 The tour soon proved sufficiently strenuous for her that she began gulping down milkshakes in an effort to restore lost weight to her 5-foot-8, 117-pound frame.But there was more to the Tunnel of Love Express than just what Springsteen had planned.On stage, Scialfa had now become Springsteen's principal vocal partner (a role held in the past by the departed Steve Van Zandt) as well as principal foil (supplanting Clarence Clemons), and in this number and others, the way Springsteen and Scialfa approached each other, and how they held their bodies as they sang together, made their byplay the center of the show right from the "Tunnel of Love" opener.