“Because the engineer’ll think there is something wrong on the bridge and stop.  It’ll be dead easy.”

Bob’s eyes were almost popping out of his head, as, afraid to peep over the top of the car, he stared at the boards as though striving to see through them.

Straining his ears to catch every word, he heard another of the plotters begin to speak, when a train thundered past, effectually cutting off all conversation with its roar.

Though Bob did not know it, so absorbed was he in listening, less than five minutes had passed since he had started back for the caboose.

With the necessity of making a quick shift to the siding, the conductor of the freight train had momentarily forgotten the presence of his youthful charge, and when at last he did remember, it was with the supposition that he had remained in the cab with the engineer.

Accordingly, upon receipt of orders to proceed, Hosmer decided to let Bob ride longer in the cab, and shouted to his men to get aboard, waving his arm in the “go ahead” signal to the engineer.

But Bob had heard the shouts, and divining their meaning, jumped to the track, having no relish for riding farther in his dangerous position between the cars.

Fortunately, both the engineer and conductor saw the boy, as he leaped to the ground, and the signal to start was not obeyed.

Recovering his balance, Bob ran toward Hosmer.

As he drew near enough for the conductor to see his white, excited face, he exclaimed: 

“Where have you been?  I thought you were in the cab with Barney.”

“I—­I tried to go back over the cars,” stammered Bob.

“Barney shouldn’t have let you.  It’s too dangerous for a greenhorn.”

Wincing at the words, which slipped out unconsciously as the conductor thought of what might have happened to the boy, Bob hastened to defend the engineer by saying: 

“Mr. Barney didn’t know I was going.  I wanted to surprise you by showing you I could go back without your help.  And—­and then the train started, and I had to hang on to a coal car.”

“Well, so long as you didn’t get hurt, it’s all right.  But don’t try it again.  Now, run back and climb into the caboose.  Let’s see how quick you can do it.”

The last was a diplomatic means to make the boy hurry, for the conductor was anxious to start the train, yet would not until he saw his charge safe in the caboose.

And his ruse was successful, for Bob, eager to show his speed, raced down the track and quickly swung aboard.

Smiling, Hosmer again signalled to Barney, the train started, and as the last car reached him, the conductor climbed on.

“Have any trouble when we started?” one of the brakemen was asking Bob as Hosmer entered the car.

“Pretty near.  I was just crossing from a high to a low car, when the jerk came.  But I managed to hang on.”