The Great Circus Train Robbery — Nancy Means Wright

Second of the Northern Spy mysteries, following the Agatha winner The Pea Soup Poisonings. Who stole three red rail cars from Spence's antique circus train? The hair-raising quest takes Zoe and Spence from a neighbor's murky basement to the Quirkus Circus to help two wacky clowns -- until one of them disappears… Agatha Finalist for Best Children's/Young Adult Novel. Young Adult/Juvenile Mystery by Nancy Means Wright; originally published by Hilliard & Harris