h. Tom was
earnestly inspecting the more delicate parts of the mechanism while Ned
(and proud he was to do it) handled the levers. Once on the main line
he moved the controller forward. The machine began to pick up speed.

The drumming of the wheels over the rail joints became a single
note--an increasing roar of sound. The electric locomotive shot up the
grade. The arrow on the speedometer crept around the dial and Ned's eye
was more often fastened on that than it was on the glistening twin
rails which mounted the grade.

Black-green hemlock and spruce bordered the right of way on either
hand. Their shadows made the tunnel through the forest almost dark. But
Tom had not seen fit to turn on the headlight.

"How is she making out?" asked the inventor, coming to look over his
chum's shoulder.

"It's great, Tom!" breathed Ned Newton, his eyes glistening. "She eats
this grade up."

"And it's within a narrow fraction of a two per cent.," said the
inventor proudly. "She takes it without a jar--Hold on! What's that
ahead?"

The locomotive had traveled ten miles or more from Half Way. The
summit of the grade was not far ahead. But the forest shut out all view
of the station at Cliff City and the structures that stood near it.

Right across the steel ribbons on which the hercules 0001 ran, Tom had
seen something which brought the question to his lips. Ned Newton saw
it too, and he shouted aloud:

"Tree down! A log fallen, Tom!"

He did not lose completely his self-control. But he grabbed the levers
with less care than he should. He tried to yank two of them at once,
and, in doing so, he fouled the brakes!

He had shut off connection with the current. But the brake control was
jammed. The locomotive quickly came to a halt. Then, before Tom could
get to the open door, the wheels began spinning in reverse and the
great Hercules 0001 began the descent of the steep grade, utterly
unmanageable!

Chapter XIX

Peril, The Mother of Invention

Tom Swift's first thought was one of thankfulness. Thankfulness that he
did not have a drag of fifty or sixty steel gondolas or the like to add
their weight to the down-pull. The locomotive's own weight of
approximately two hundred and seventy tons was enough.

For when the inventor pushed Ned aside and tried to handle the
controllers properly, he found them unmanageable. There was not a
chance of freeing them and getting power on the brakes. The Hercules
0001 was back