For want of a larger horse

“You’re going to be the most important person in Orbital City in about two day’s time,” said the colonel. “Not much engineering repair work for you to do now though, until we sort out those remaining pockets of resistance.”

Atul went in search of a drink.

Although the skirmishing was over on the other side of the vast wheel-shaped structure, every so often there was a thump that made the infrastructure shake. Some genius had disconnected the air pressure alarms, probably due to the incessant noise, so he clutched his emergency air tank, and flinched with each new vibration of the floor.

The bar was up near the outer rim of the wheel, and almost at full Earth gravity. Atul was surprised to find civilians inside: two evident lushes had stacked the remaining bottles of alcohol in one corner, and were battling their way through them valiantly. A pyramid of empties marked their advancement.

Up on the tiny stage, a musician noodled away on a battered electric guitar. He stopped when Atul entered the room, laid down his instrument, and stepped unsteadily down from the low platform. “Jan,” he said, introducing himself, pronouncing his name in the Dutch manner, as if it started with a “y”.

“What are you still doing here?” Atul asked, puzzled to see civilians.

“Couldn’t take it with me,” Jan said, motioning with his head towards the stage.

“The guitar?” Atul asked.

“No, that’s a knock-off,” Jan said. “The amp. It’s custom-made, a one-of-a-kind antique.”

Atul glanced at the cabinet, which was a hefty-looking wooden box, with a speaker grill, and several inscrutable dials on top, the sole inhabitant of one corner of the stage. It was connected to the guitar by a coiled black cable. “They aren’t restricting baggage by weight any more,” he said. “Almost everyone has gone already.”

Jan sighed. “The amp is two centimetres too large to fit through a standard airlock,” he said. “I brought it up via the old cargo berth, but there’s only passenger ships coming here now to pick up people, so I can’t take it out that way. I’d love to get out of here and go find a gig somewhere safe, but I just can’t bring myself to leave it.”

“You can’t rotate it around and try to squeeze it through?” Atul asked. The box appeared to be slightly oblong.

“Tried,” Jan said. “The inside diameter of the port is exactly 800 millimetres. That’s about 31 inches.” He held up his hands to illustrate.

“Give me a second,” Atul said. He could tell that Jan was winding himself up for a tale, and he wanted something to drink first. He stepped over to the drunks’ great mound, and liberated two bottles randomly. They didn’t appear to notice. He passed one to Jan, and then examined the other bottle in his hand. The label was printed in Japanese, and there was no way for him to tell what it contained through the smoky glass. He twisted off the cap and took a small experimental swig. Tasted like the smoothest fire in Low Earth Orbit.

“Go on,” he said.

“There’s a historical reason why those passenger hatches are so small,” said Jan. “The outside diameter of fifty inches was as big as they could fit on the old spacecraft that everyone was flying back when the standard was designed. Any idea why they were so narrow?”

“Nope,” said Atul. There was a thump, and he checked his tank again.

“They had to move them around using railroads,” said Jan. “Those had a standard gauge of exactly fifty-six and a half inches, which limited how wide they could make them.”

Atul took another sip from his bottle of undisclosed. It still combusted effortlessly.

“The Americans copied that standard from the British all the way back in the nineteenth century,” said Jan. “The British picked that size because it was the standard breadth of Roman military wagons from two and a half millennia ago. They probably just thought that the Romans knew what they were doing. But those carts were just designed so that two horses could fit comfortably side by side in the traces.”

Atul still didn’t say anything, but his impatience may have been showing, because Jan said, “I’m sorry, you probably really need to go.”

He paused for a moment, then added, pitiably, “I can’t help but wonder what would have happened if those horses had been a tiny bit fatter.”