The lads ceased their talking instantly and listened with straining ears.
"What is it?" breathed Tad.
"It's a car going through the tunnel."
"Is—is it the red car?"
"I don't know. It's a gravity car—traveling along down grade by its own weight, so it must be on track two."
"What can we do?" asked Ned.
"Not a thing, my boy, only keep cool. It will not help matters any to get excited."
"We are not!" replied Ned firmly. Each of the other two boys protested that they had never been less excited, which brought an approving smile from their guide, who was filled with admiration for the plucky lads. The fact is, his admiration had been steadily growing since he had seen their achievements from the time Tad Butler had first staggered into the Red Star mining camp a few days before.
"I guess the car is going through safely. I am glad—"
Tom Phipps did not finish the sentence. He was interrupted in a way that shook all the speech out of him, as it did from the rest of the party.