Faster and faster it ran, the dust flying in a cloud about it. "Better put the brakes on a bit," called the conductor. "It's gettin' kinder speedy, Hank!" The motorman twisted the handle. There was a grinding noise as the shoes took hold on the wheels. Then a chain snapped and the car seemed to leap ahead. "The brake's busted! I can't stop the car!" yelled the motorman. Vainly he twisted at the handle. Then, seeing he could not stop the trolley car he made a desperate jump off the vehicle and landed in a heap on the side of the road, rolling over and over. "Reverse the current!" cried one of the passengers, to the conductor. "That ought to stop her!" The conductor made his way to the front platform and turned the reversing lever. Then he applied the current. But it was no use. With a blinding flash and a report like that of a gun a fuse blew out, and that crippled the car completely so far as the electric current was concerned. "Everybody jump!" cried the conductor. "There's a curve at the foot of the hill, and we'll all be killed if we stay on!" One by one the passengers leaped from the car. Several were badly hurt by the falls they got. Meanwhile the trolley was tearing down the hill at a terrific rate of speed. "Shall we jump?" asked Mark of Jack. "We'll be killed if we do," was Jack's answer. "And we'll be killed if we stay aboard," said Mark. "Not if I can help it," cried Jack as he started for the rear platform. "What are you going to do?" asked Mark. "Put on the other brake. They never thought to try this one! Maybe it will work and stop the car!" Then Mark saw what Jack was up to and went to help him. The shabbily dressed man seemed undecided what to do. He stood up, holding to the straps to prevent himself from being tossed from side to side as the runaway trolley swayed. He watched the boys curiously. The lads, reaching the rear platform, twisted at the brake handle with all their strength. They could feel that the chain was still intact. But would the shoes grip the wheels with force sufficient to stop the car? There was a shrill screech as the brakes were applied by the boys. With all their might they turned the handle, winding the chain up tighter and tighter. At last they could not budge it another inch. Then they waited anxiously. The car never slackened its speed. So great was the momentum that had both sets of brakes been in working order it is doubtful whether they would have stopped the vehicle. The speed was so great now that one of the journals became hot and the oily waste that was packed in it caught fire, making what railroad men term a "hot box". "I guess we're done for," groaned Mark. "We certainly haven't checked the speed any," Jack admitted. "But wait a minute." He began stamping on the floor of the platform. "What you doing?" cried Mark, for he had to shout to make his voice heard above the roar and rattle of the car.