The British troops stood gallantly to their work, and returned volley for volley.  They fought on doggedly.  Suddenly the armored train shot up the line which the British were holding, and Hal brought it to an abrupt stop.

Right and left the train poured in broadsides of machine-gun fire, mowing down the Germans at every yard.  The Germans fell in heaps, and, as if by a miracle, both sides of the track were suddenly lined with high piles of the dead.

The little troop of British received this unexpected aid with a great cheer, broke from cover and dashed in pursuit of the great mass of Germans, who now were fleeing on all sides.

But the success of the British was destined to be short-lived.  Hal and Chester, in the cab of the locomotive, had just raised a loud cheer when there was a terrific explosion, followed by a thundering crash, and both lads were hurled violently to the floor of the cab.

Chester, with blood flowing from a gash in his forehead, was the first to pick himself up.  In falling his head had come in contact with a sharp projection of some kind.  He was terribly dizzy, but his head was still clear.

He stooped over Hal, and at that moment the latter raised himself on his elbow and then got to his feet unsteadily.

“Great Scott!  What was that?” he gasped.

Chester did not reply.  Instead he swung out from the cab and glanced back over the train—­or rather where the train had been.  And what a sight met his gaze!

The train of armored cars was gone.  Alongside the track lay pieces of wreckage, and many bodies and pieces of what had once been machine guns.

Hal peered over Chester’s shoulder.

“Another shell,” he said slowly.  “But how does it happen we were not killed also?”

“I don’t know,” said Chester, “but I judge the shell must have struck in the middle of the train.  Look, there is nothing left but the engine.”

It was true.  In some unaccountable manner the engine had escaped scot free.  At that moment Hal, who had glanced out from the other side of the cab, made a startling discovery.

“Wow!” he shouted.  “Here come the Germans again—­thousands of ’em.  We are goners, now, sure.”

But, before Chester could reply, Hal jumped forward.  With one hand he released the brakes and threw the throttle wide—­and the huge locomotive leaped suddenly forward.

“It’s our only chance,” Hal shouted to Chester.  “The track behind is covered with wreckage, and it is impossible to go that way.”

That the Germans understood their ruse was soon apparent.  There was a shout from the oncoming horde, and the sharp crack of rifles and bullets began to spatter against the side of the engine.

“Well, we’ll give ’em a chase, anyhow,” said Hal grimly.

He opened the throttle even wider.

CHAPTER X.