In the distance the sound of firing could be heard, and occasionally a
shell burst close to where the boys were standing. But they had been
through their baptism of fire, and paid little heed to these
messengers of death.

"They say that these trains have proven immense factors in sudden raids
on the enemy," said Chester.

"Yes," agreed Hal, "and it is easy to see that among light armed troops
they could do great execution. It would even take very heavy artillery
fire to make an impression on those steel sides. Besides--"

He broke off with a sudden exclamation.

"Look out," he cried, and leaped back, pulling Chester forcibly along.

A second later and there was a terrific explosion. A German shell had
burst within a few feet of where the two lads had been standing.

A crowd of troopers, who had been idling about a few yards from the
train, disappeared with the deafening report, and when the smoke had
cleared away they were nowhere to be seen. They had been blown to atoms.

The boys rushed forward, but, even as they did so, they halted at the
sound of a sudden cry, and, turning their faces up the track, they beheld
a mounted officer galloping swiftly toward them. An officer dropped off
one of the cars of the train, which, fortunately, had not been touched by
the explosion, and hurried to meet the newcomer.

"Who is in charge of this train?" demanded the horseman, throwing himself