"Kingwood Tunnel," says Duffy quietly. "Old, old tunnel, back when they built things super-solid and dug as deep as Vaults just to give the trains places to go."

Aaron nods. "Most of Tunnelton was folks who lived in or near that tunnel," he says. "Did a fair job keepin' it in repair, too, least as far as anyone can 'round here, but no man alive c'n stop a landslide when the mountain decides it wants to move."

"Can't get through the tunnel any more, no point tryin'," Duffy says.