Whose big rig?

"This nonfiction follow-up to Whose Truck? features six kinds of specialized rigs used to construct a light-rail system-a tunnel borer, an excavator, a bulldozer, a tie dragon, a tamping machine, and a bucket truck-with five different parts of each rig properly labeled. The answer to each inquiring refrain of "Whose rig is this?" is revealed under a gatefold, engaging the reader in an informative guessing game about construction machines and thei...