Immediately, powerful pneumatic mechanisms roared to life and shoved the cylinders outward in both directions, right out through the wooden sides of the boxcar, with a shuddering crash. Splinters flew everywhere. The rocket engines were now sticking out on either side of the train.

Kate ran away as fast as she could.

A calm voice began to count down from ten. Kate thought maybe it should’ve picked a higher number to count from, and if she ever had the chance, she would report that as a design flaw. She made it through the boxcars, through the candy car, across the flat car, and all the way to the library car before the rockets kicked in.

Kicked was the right word: It felt like a giant soccer player had reared back and booted the train right in the caboose. Or like it really was a silver arrow and it was being fired from a huge bow. Kate flew right off her feet and slammed into the back wall of the library.

She stuck there like Velcro: The train was accelerating so fast it pinned her against the wall. Everything else in the room that wasn’t nailed down joined them on the back wall. (Fortunately somebody had thought to nail down the furniture. Though not any of the cushions.) Fighting the g-forces, Kate could just turn her head far enough to see the world outside racing past in the window, faster and faster, even faster than they’d gone down the mountain. The whole train was shuddering and rocking with the force of the acceleration. She couldn’t see them, but the rockets were now shooting out bright blue-white spikes of flame behind them, shoving the train forward faster and faster and faster toward the edge of the cliff.

The pressing question in Kate’s mind was, did the rockets have enough power to push an entire steam train straight up a more-or-less vertical track? And if they did have enough power, where was that track going to take them?

The fields outside disappeared: The Silver Arrow had cleared the cliff. Now there was nothing but empty blue sky in the windows, and the train was still accelerating. Then it started tilting back, back and back and back as the track under it bent up toward the sky, back and farther back till every nerve in Kate’s body was screaming, Stop! Stop! For the love of all that is good and reasonable, stop!