It may be wondered what had happened to the worthy and patient Ching. The Chinaman was far too good a cook to have his talents wasted in the canal zone, and from the very beginning was installed in that capacity at Phineas Barton's quarters, thus relieving the lady who had formerly done the work. The change, indeed, was all for the best, for now Sadie received more attention. Three months almost to a day from the date when Jim had begun to run the motor drill the machinery got out of order. "One of the big ends of a piston flew off," he reported to the official, when the latter arrived. "Before I could stop her running the piston rod had banged a hole through the crank case, and I rather expect it has damaged the crank shaft." It was an unavoidable accident, and meant that the machine must undergo repair. "You'll have to be posted to another job meanwhile, Jim," said the official. "Of course I know that this is none of your doing. We shall be able to see exactly what was the cause of the accident to that piston rod when we've taken the engine down. Perhaps one of the big end bolts sheered. Or there may have been a little carelessness when erecting, and a cotter pin omitted. But I don't think that: my staff is too careful to make errors of that sort. How'd you like to run one of the inspection motor trolleys? They were asking me for a man this morning; for one of the drivers is down with fever. You'd be able to take on the work at once, since you understand motors. Of course there isn't any timetable to follow. You just run up and down as you're wanted, and all you've got to learn really is where the switches and points are; so as to be able to sidetrack the car out of the way of the dirt trains." So long as it was work in connection with machinery Jim was bound to be pleased, and accepted the work willingly. The next day he boarded the inspection car at Gatun, and within half an hour had made himself familiar with the levers and other parts. Then he was telephoned for to a spot near Gorgona, and ran the car along the rails at a smart pace. Twice on the way there he had to stop, reverse his car, and run back to a siding, there to wait on an idle track till a dirt train had passed. "You'll get to know most every switch in a couple of days," said the negro who was in charge of this particular point, "and sometimes yo'll be mighty glad that you did come to know 'em. Them spoil trains don't always give too much time, particularly when there's a big load and they're coming down the incline from way up by Culebra." The truth of the statement was brought to our hero's mind very swiftly; for on the following morning, having run out on the tracks ahead of an empty spoil train, and passed a passenger train at one of the stations, he was slowly running up the incline into the Culebra cut when he heard a commotion in front of him. At once he brought his car to a standstill beside one of the points.