Freed of his well-paying gig as Bruce Springsteen’s gnome-like guitar foil, Nils Lofgren sounds thrilled to grab the reins again for his first solo album in six years. One of rock’s perennial-underdog guitar heroes, Lofgren spends a good chunk of time on Silver Lining piling layer upon layer of fluid, lyrical leads atop songs that range from swaying ballads to roadhouse shuffles. Luckily for us, he’s more than an air-guitar fanatic’s dream. Ever the incurable romantic, Lofgren at 38 still sings in the softly coarse voice of the shy kid unable to approach that special someone, and he writes songs to match. One of them is the single ”Valentine,” a gumdrop ballad featuring a guest gargle by Springsteen himself. A few tracks are little more than well-worn white R&B riffs with throwaway lyrics. But after years of second-banana status and flop albums that would demoralize the best of us, Lofgren displays a feisty exuberance on Silver Lining that’s close to inspirational. There may be no better example than the closing track, ”Girl in Motion,” where, over a soft pulse, Lofgren gently laments the departure of his latest flame, who has both his heart and a train ticket in her hand. When he pulls back from the microphone to play a solo that wails and cries like a human voice, you forget the years of wasted opportunities and just hope the couple works out their differences and she doesn’t board that train.