Engineer Maclure was leaning out of the cab window, watching for the conductor's signal, when Brockway and Gertrude came up.

"Didn't know but you'd backed out," he said, jocosely, when they had climbed aboard.

"Oh, no, indeed; we had to get word to my father," said Gertrude.

The engineer waved them across the cab. "Make yourselves at home; the 926 belongs to you as long as you want to own her. Just you pre-empt Johnnie's box over there, Fred, and make the young lady comfortable."

Brockway stuck a propitiatory cigar into the pocket of the fireman's jumper, and proceeded to carry out his instructions. Before the tardy signal came, Gertrude was perched upon the high seat, with her skirts gathered up out of harm's way, and Brockway had fashioned a pad out of a bunch of waste and tied it upon the boiler-head brace at her feet.

"It's hot," he explained. "When she begins to roll you can put your foot against that and steady yourself. Are you quite comfortable?"

"Quite; and you?" She looked over her shoulder to ask the question, and the strong red glow from the open door of the fire-box glorified the sweet face.

"Comfortable? No, that is hardly the word for it"—he tried the window-fastening, that he might have an excuse for bending over her—"I'm happy; happy to my finger-tips. Do you know why?"

He sought to look up into her face, but at that moment the red glow of the fire-light went out suddenly with the crash of the closing door, and the clangor of the bell made her reply inaudible. None the less, by the dim, half light of the gauge-lamp he saw her eyelashes droop and her lips say No.

For a passing instant the social barriers went down and became as though they never were. Standing beside her and blessing the clamor that isolated them, he said:

"Because I am here with you; because, no matter what happens to either of us in the future, no one can ever rob me of this."

He half expected a rebuke, and waited a moment with becoming humility. When it did not come, he swung himself into the seat behind her and held his peace until she spoke again. That was five full minutes afterward. For that length of time Gertrude was crushed under an avalanche of new sensations. The last switch-light in the Carvalho yards had flashed to the rear, and the 926 was quickening her speed with sharp little forward lunges under Maclure's skilful goading. The dizzying procession of grayish-white telegraph-poles hurling itself past the cab windows; the thousand clangorous voices of the great machine; the intermittent glare from the fire-box door, alternating with the fiery shower of sparks pouring from the smoke-stack—it was a bit of pandemonium detached and dashing through space, and she sat cowed and stunned by the rush and the uproar. But presently the warm wine of excitement began to quicken her heart-beats.

"Isn't it glorious!" she exclaimed, trying to look back at him.

It is quite possible for two persons to converse in the cab of a flying locomotive, but the factor of distance must be eliminated. Wherefore he bent over her till his mustache brushed the pink ear.

"I am glad you like it. Are you still quite comfortable?"

"Yes, indeed; thank you. How fast are we going now?"

"About twenty-five miles an hour; but we'll double that when Maclure gets her warmed up."

"Double it! Why, we seem to be fairly flying now!"

"Wait," said Brockway.

Maclure was sitting sphynx-like on his box, coming to life now and then to reduce the angle of the reversing-lever, or to increase that of the throttle. The fireman labored steadily, swaying back and forth between the coal-chute and the fire-box door, his close-fitting cap on the back of his head, and Brockway's cigar,—unlighted, in deference to Gertrude,—between his teeth.

"What dreadfully hard work it must be to shovel coal that way all night," Gertrude said, following the rhythmic swing of the fireman's sinewy figure with her eyes.

"He's getting his fire into shape, now," Brockway explained. "He'll have it easier after a bit."

"Why doesn't he smoke his cigar?"

Brockway smiled. "Because, down under the grime and coal-dust and other disguises, there is a drop or two of gentle blood, I fancy."

"You mean it's because I'm here? Please tell him to light his cigar, if he wants to."

Brockway obeyed, and the fireman unbent and bobbed his head in Gertrude's direction. "Thank ye, ma'am," he shouted, with a good-natured grin on his boyish face; "but I'm thinkin' a dhry smoke's good enough for the lady's car"—and he bent to his work again, while the endless procession of telegraph-poles hurtled past with ever-increasing swiftness, and the sharp blasts of the exhaust lost their intermittence, and became blent in a continuous roar.

Presently, the laboring engine began to heave and roll like a storm-tossed vessel, and Gertrude was fain to make use of the foot-rest. Being but a novice, she made unskilful work of it; and when her foot slipped for the third time, Brockway took his courage in both hands.

"Just lean back and brace yourself against my shoulder," he said; "I'm afraid you'll get a fall."

She did it, and he held himself in watchful readiness to catch her if she should lose her balance.

"Is that better?"

She nodded. "Much better, thank you. Have we doubled it yet?"

Brockway took out his watch and timed the revolutions of the flying drive-wheels. "Not quite, but we're bettering the schedule by several miles. Do you still enjoy it?"

"Yes, much; but it's very dreadful, isn't it? I don't see how he dares!"

"Who? Maclure?"

"Yes; or anyone else. To me it seems braver than anything I ever read of—to drive a great thing like this with so many precious lives behind it. The responsibility must be terrible."

"It would be if a fellow thought of it all the time; but one doesn't, you know. Now I'll venture a guess that Mac is just speculating as to how much of the 'Kestrel's' lost time he can get back between this and the end of his run."

But the shrewd old pioneer with the Scottish name was thinking of no such prosaic thing. On the contrary, he was wondering who Miss Vennor was; if she would be a worthy helpmate for the passenger agent; and if so, how he could help matters along.

The switch-lights of Arriba were twinkling in the distance, and his hand was on the whistle-lever, when the engineer reached a conclusion. The next instant Gertrude shrieked and would have tumbled ignominiously into the fireman's scoop if Brockway had not caught her.

"How silly of me!" she said, shame-facedly. "One would think I had never heard a locomotive whistle before. But it was so totally unexpected."

"I should have warned you, but I didn't think. This is Arriba; do you want to go back?"

Gertrude was enjoying herself keenly, after a certain barbaric and unfettered fashion hitherto undreamed of, and she was tempted to drink a little deeper from the cup of freedom before going back to the proprieties. Moreover, there was doubtless a goodly measure of reproof awaiting her, and when she remembered this, she determined to get the full value of the castigation.

"I'll go on, if you'll let me," she said.

"Let you!" Brockway had been trembling for fear his little bubble of joy was about to burst, and would have multiplied words. But before he could say more, the 926 thundered past the station and came to a stand.

Maclure released the air-brake, and clambering down from his box, dragged the passenger agent from his seat and so out to the gangway.

"Say, Fred, is she goin' back?" he whispered.

"No, not just yet."

"Bully for her; she's got sand, she has. Reckon you could run a spell and talk to her at the same time?"

Brockway's nerves tingled at the bare suggestion. "Try me and see," he said.

"It's a go," said Maclure. "Get her over there on my side, and I'll smoke me a pipe out o' Johnnie's window. Swear to bob I won't look around once!"