His hand clenched the implement he had used to pry away the bars, and Bart now saw what it was.
The object the mysterious robber was utilizing for burglarious purposes, was the signal flag used at the switch shanty where Lem Wacker had been doing substitute duty that day.
It consisted of a three foot iron rod, sharpened at the end. At the blunt end the strip of red flag was wound, near the sharp end the conventional track torpedo was held in place by its tin strap.
"Lemme go"; again growled the man.
"Never!" declared Bart.
The man's left arm was free, and he swung the iron rod aloft. Bart saw it descending, aimed straight for his head. If he held on to the man he could scarcely evade it.
He let go his grip, ducked, made a pass to grasp the burglar's ankle, but missed it.
An explosion, a sharp flare, a keen shock filled the air, and before Bart could grip the man afresh he had sprung from the platform and vanished.
At the same instant the flag rod clattered to the boards, and a second later, rubbing his face free from sudden pricking grains of powder, Bart saw what had happened.
The blow intended for him had landed upon one of the iron bars of the window with a force that exploded the track torpedo.