ely:
"X-x-x---a-a-a---b-b-b."

The operator repeated it. Black nodded. Once more the instrument
clicked.

"The other box relay man signals that he has it," nodded Black's
present operator.

"Listen! Everyone of you! Not a sound in this outfit," commanded
'Gene Black.

For fully three minutes the intense silence continued. Then Black
turned again to the operator, saying:

"Ask the other box relay man if anything has happened near him?"

A minute later Black's operator reported:

"He says: 'Yes; happened successfully.'"

"Good!" laughed Black, a look of fierce Joy lighting up his eyes.
"Now, Reade, I guess you'll admit yourself beaten. An electric
spark has touched off a charge of giant powder under the roadbed.
The rails have been blown skyward and a big hole torn out of
the roadbed itself. Even if you had a wrecking crew at the spot
at this moment the road couldn't be prepared for traffic inside
of twenty-four hours. NOW, will your through train reach Lineville
tonight? Can your road save its charter _now_?"

Tom Reade's face turned deathly white.

'Gene Black stood before him, gazing tauntingly into the eyes
of the Young Chief engineer.

CHAPTER XXIII

BLACK'S TRUMP CARD

"You scoundrel---you unhung imitation of Satan himself!" gasped
Reade, great beads of perspiration standing out on his face.

"Oho! We're fools, are we?" sneered Black "We're people whom
you can beat with your cheap little tricks about a different signature
for each station on the line, are we? For that was why the conductor
refused the false order at Brewster's. He has a code of signatures
for train orders---a different signature to be used for messages
at each station?"

Black's keen mind had solved the reason for the conductor's refusal
to hold his train on a siding. The conductor _had_ been supplied
with a code list of signatures---a different one for each station
along the line.

"Now, you know," mocked Black, enjoying every line of anxiety
written on Tom Reade's face, "that we have you knocked silly.
You know, now, that your train can't get through by tonight---probably
not even by tomorrow night. You realize at last---eh?---that
you've lost your train and your charter---your railroad?"

"I wasn't thinking of the train, or of the road," Tom groaned.
"What I'm thinking of is the train, traveling at high speed,
running into that blown-out place. The train will be ditched
and the crew killed. A hund