Shorty noticed that a few still managed to clamber on at each stop and once they did, the soldiers turned a blind eye.

“They sleep, eat, shit up there,” one soldier told him. “They don’t dare get off in case they never get back on again.”

“We lose a few when we go through tunnels,” his companion said. “On the last trip, some of them fell asleep sitting up. They got knocked off even though the conductor blew the whistle several times to warn them.”

By now Shorty could tell from the activity around the locomotive that their train was getting ready to move again. He reached down and thumped the boxcar door. It slid open and the two classmates who had been riding on the roof with him climbed down the handholds to go inside.

“Next shift,” he shouted. Their boxcar was crammed with cargo and badly ventilated. They’d agreed to take turns sitting on top of the car to free up enough space so that the students inside could actually sit down. Shorty didn’t like closed spaces and was taking an extra shift on top.

When the train began moving again, he sat facing the back of the train. It was better to have the rush of air at his back rather than blowing down the front of his padded vest. The steel panels of the railcar roof were slippery, but he pushed his feet against the raised edge of a metal seam and felt more secure.

The three students shared the roof with six men from the town of Changchow, all members of a carpenters’ guild. The men had bribed soldiers to let them get on the roof; they were also riding south to Changsha, chasing work. The carpenters deferred to the students, who were legitimate passengers, but they defended the roof fiercely, demanding money from those who tried to climb on. “We paid to sit on this railcar, eh,” they shouted. “Pay up or stay off.”

The rocking motion of the train was soothing. The tracks passed through a forest dense with bamboo and pine. Tall yellow stalks and dry leaves waved above Shorty, splitting the sunshine into strips of light that flashed over the railcars, a rhythmic and hypnotic effect that made him sleepy. He jerked up, knowing how easy it would be to roll off the roof. When the train emerged from the shadows of the forest, Shorty blinked up at a sky no longer blue but fading into dusky sunset, shades of pink and amber staining the horizon.

He watched the forest recede, fought off drowsiness. Just for a few moments, he told himself as his eyelids closed and his mind strayed into the realm between sleep and waking.