A stroll across Chattanooga, Tennessee's Walnut Street bridge - one of the longest pedestrian bridges in the world - introduces ANTIQUES ROADSHOW's discussion of carved wooden folk-art walking canes. Appraisal highlights: an heirloom 18th-century Chippendale tall chest; a unique piece of presidential memorabilia: an "8-ball" presented to Harry Truman in 1948 by the Los Angeles Press Club; and a pristine Lionel train set, circa 1930, valued at $2,500 to $3,000.