How he had failed to discover them from the top of the other car, he could not understand, but he soon ceased to wonder, in his eagerness to catch every word uttered by the unseen tramps.
"That's easy," replied the voice the boy recognized as having made the threat to "get even."
"Cut out that talk, and get down to business," growled a third voice.
"All right, 'Bo. We can put all sorts of crimps into this road by 'holding up' the night express! The officials of this road, whose men are too stingy to let a fellow ride on the blind baggage, are boasting they haven't had a 'hold-up' for years."
The various exclamations with which this wicked plan was greeted, told Bob not only that it met the approval of the tramps, but that there were more than two of them.
The full danger of a "hold-up" the boy did not realize. He remembered, however, having read of such occurrences out West where passengers were terrorized and robbed of money and jewelry.
But his speculation was again interrupted by the renewal of the conversation.
"That will sure set us even, but when can we do it?" inquired a voice eagerly.
"And get away safely?" added another.
"There's only one place," responded the voice of the man who had suggested the plot.
