Peter Sis, . . HarperCollins/Greenwillow, $17.99 (64pp) ISBN 978-0-06-057838-1

Uncle Sam conducts the patriotic engine of this line of 50 railroad cars (one per state), and Washington, D.C., brings up the rear as caboose. Czechoslovakian-born Sís combines his love for his adopted country (his home for more than two decades) with his admiration for antique circus wagons (from an introductory note). The cars appear chronologically, according to their date of statehood. Readers will pore over the unique design of each, which incorporates the state's flag, motto, nickname and the genesis of its name, as well as labeled images of the state tree, flower and bird. Underneath the cars, Sís lists the state capital, then repeats the state tree, flower and bird, adding a piece of trivia (e.g., "In Barrow, Alaska's northernmost point, the sun doesn't set for 84 days during the summer months"). Given the prescribed space allotted to each state, the duplication of some of these facts comes at the expense of additional information. But the wagons teem with interesting details (explained in an endnote); they include miniature portraits of presidents or other celebrities who hail from the state (Ben Franklin tops the Pennsylvania circus wagon), milestones (Ohio had the first professional baseball team; women could first vote in Wyoming) and relevant symbols (Mount Rushmore for South Dakota). Sís's signature fine black line limns entire vignettes while his watercolor wash adds depth and perspective. He gives both youngsters hungry for state facts and those casting about for unusual historical morsels ample reason to climb aboard this festive train. Ages 6-up. (Sept.)