The story of the world's most audacious infrastructure project. Less than a decade ago, China did not have a single high-speed train in service. Today, it owns a network of 14,000 miles of high-speed rail, far more than the rest of the world combined. Now, China is pushing its tracks into Southeast Asia, reviving a century-old colonial fantasy of an imperial railroad stretching to Singapore; and kicking off a key piece of the One Belt One Road initiative, which has a price tag of $1...