Snatching the General — Tim Champlin

Cousins, Brad and Glen Casemont, have lost a $3 gold coin worth half-million dollars that they borrowed without permission from Brad's father.

From inside a cave, the boys have gone back in time twice. During each adventure, they see the coin, or get it in their hands, but not for long. They can't seem to bring it back to the present. Even though they have no control over when or where they go, they try a third time and are carried back to April 12, 1862, where they land aboard a train near Atlanta. The train, pulled by the locomotive, the General, is being hijacked by Union spies. The boys are caught in the middle of this and forced to travel with the raiders as the train flees north toward Chattanooga, with the Confederates on their tails.

Where is the coin the boys came to find? The leader of the raiders, James Andrews, uses it to buy wood to fire the boilers of the steam locomotive, the General. Brad and Glen try desperately to buy the coin from the wood yard man, but fail.

In the wild chase that follows, they forget the coin as they hold on to the top of the train as it races northward. They realize that whichever side they wind up with, they'll either go to jail or get hanged. They've got to escape, but the train is going too fast to jump. And there's a tunnel is coming up…