The U.S. standard railroad gauge—the width between the rails—is 4 feet, 8 ½ inches.
Strange number, isn’t it? You’d think something so crucial would be more logical.
So why that width?
Because American railroads were built by British expatriates, and that’s how they did it in England.
Why did England do it that way?
Because the tramway builders used the same tools and measurements they used for wagons.
Why were wagons that width?
Because any other size wouldn’t fit into the deep ruts already carved into the ancient roads.
Who carved the ruts?
The Romans.
And why were Roman chariots that width?
To fit the rear ends of two horses.
So today’s massive rail system—millions of tons of steel, cargo, passengers—still runs on measurements set by two Roman horses - two thousand years ago.