China’s high-speed rail network is easy to admire and surprisingly easy to use once you know the correct station. The difficult part for many first-time visitors happens earlier: a single city can have several major stations, and a traveler often starts with a hotel, airport, attraction, or street address—not a station name. I initially wanted to build a practical transport tool for foreign visitors in China. After reading travel questions, the recurring problem was not simply “how do I buy a...