An instant later, to the surprise of the boys, no less than Mr. Post, there was a quick application of the air brakes, so much so that the passengers were nearly thrown from their seats. Then with a grinding and shrieking the train came to a stop.
"What did I tell you?" inquired Professor Punjab.
"Well I'll be horn-swoggled!" exclaimed Mr. Post.
"What's the matter?" asked several travelers.
The boys had hurried to the front of the car. They were met by a brakeman.
"Don't be alarmed," he said. "There is no danger."
"What was the trouble?" asked Jack.
"There was some obstruction on the track, a couple of ties, I believe, that fell from a passing flat car," the brakeman explained. "The engineer saw it and stopped just in time."
Professor Punjab pulled a book from his pocket and began to read, as if prophesying that trains would suddenly stop was the most natural thing in the world.