"Here it is," he said at last, when he had closely examined and smelt of a dark spot on one of the ties. "Lucky you let him clean the engine; he must have been standing in the oil trough."
"Good he had his sneaks on, too," said Roy, stooping. "It's like a stamp on a pound of butter."
It was not quite as clear as that, but if Pee-wee had prepared his sneaks especially for making prints on wooden ties he could scarcely have done better. In order to get at the main bearings of the engine he had, with characteristic disregard, stood plunk in the copper drain basin under the crank-case. The oil had undoubtedly softened the rubber sole of his sneakers so that it held the clinging substance, and in some cases it was possible to distinguish on the ties the half-obliterated crisscross design of the rubber sole.
"Come on," said Tom, "this thing is a cinch."
"It's a shame to call it tracking," said Roy, regaining some measure of his wonted spirits as they hurried along. "It's a blazed trail."
And so, indeed, it was while it lasted, but suddenly it ceased and the boys paused, puzzled.
"Listen for trains," warned Tom.
"There won't be any along yet a while," said Roy. "There's one stopped up there a ways now."
They could hear the shunting up the track, interspersed with faint voices calling.
"Here's where he's put one over on us," said Roy. "Poor kid."