BEIJING was shrouded in thick smog this week. It felt hazardous for health and played havoc with flights, which faced long delays as the airport struggled to cope. On a tight schedule, the normally routine shuttle service to Shanghai was not to be relied on. Fortunately, your correspondent had already decided to experiment with the new high-speed rail link, which runs between the cities about as regularly as the flights.

The reputation of China's high-speed rail network suffered a blow with the crash in Wenzhou earlier this year, which brought criticism that the network has been built in a rush, cutting corners on safety. Certainly the programme is ambitious, and work proceeds apace: by the end of 2012 half of the cities on China's planned 30,000km (19,000-mile) network are due to be connected. This is said to be the largest transport infrastructure project ever.

The result on the Beijing-Shanghai route is impressive: gleaming new stations at either end; spacious, clean trains (in whichever of the three classes you travel); a very smooth ride, at a speed that reaches 312kph, as an electronic display at the end of each carriage helpfully tells you. The trip to Shanghai takes about five hours, with only a couple of stops. The journey in the other direction, from Shanghai to Beijing, has a few more stops and takes about half an hour longer.

So, in normal conditions it's still quicker, if less relaxing, to fly. The train, too, is apparently vulnerable to disruption from snow. But it's now a serious competitor—on price, comfort and reliability—to flying. And, as you race by rice fields and construction sites, you get to see a bit more of China, new and old.