Kate took pride in keeping the brass fittings in the cab polished and the floor swept—she and Tom were always dropping bits of coal on their way from the tender to the firebox. When she’d first seen the cab it had looked like a mess of random pipes and levers to her, but now she could read the Silver Arrow’s controls like a book. She felt like she had a whole new set of senses: Some part of her mind was always keeping track of the water level and the steam pressure in the boiler, and the heat in the firebox, and how steep the grade was, and where the throttle and the reversing lever were set. (She totally got the reversing lever thing now.) Steam was old-fashioned technology, but it turned out that you could be a major nerd for it anyway.

They chugged uphill, switchbacking up into a steep mountainside forest. Gray slopes fell away behind them into green valleys, which wandered off and faded away into the distance. But as beautiful as it was, it was hard work climbing mountains. The Silver Arrow kept demanding more and more coal, and going slower, and slower, and slower, till after a while Kate could almost have kept up with it on foot.

She didn’t want to think what would happen if they actually stopped, or even worse, started rolling back down the mountain. Tom kept whispering “I-think-I-can I-think-I-can” to the train, like in The Little Engine That Could, and the train kept telling him to knock it off.

I’M NOT DESIGNED TO CLIMB MOUNTAINS. I’M NOT A FUNICULAR!

“I don’t know what that is, but tell me if we have to start leaving cars behind,” Kate said. “I can live without the boxcars, but I draw the line at the library car.”

I’M NOT LOSING ANY CARS

WHAT KIND OF A MONSTER ARE YOU?

“I’m just trying to help.”

WE LEAVE NO CAR BEHIND

EXCEPT MAYBE THE CANDY CAR, I’LL LET YOU KNOW

Finally, they made it to the top, where there was a pass through the mountains. By this time the Silver Arrow was barely moving at a walking pace. The shadows of the mountains stretched away for miles behind them, spilling darkly down into the valley. For one long minute they were on level ground, and everybody sat back and took a deep breath.

Then the Silver Arrow tipped forward and started down the other side of the mountain.