Five years after two high-speed trains collided in the eastern city of Wenzhou, China’s railway companies are making a comeback. It’s not easy to find value after a 51 percent rally in the MSCI China Index during 2017. So lately, sell-side banks have been telling their clients a rail renaissance story. CRRC Corp., the world’s largest maker of equipment for ...

For the social-media business, this New Year is one of grim tidings. Every day, it seems, pioneers in the field are offering mea culpas — airing regrets, expressing caution, apologizing for a technology that seems to have run amok. One former Facebook Inc. executive recently conceded that the network is “ripping apart the social fabric.” A former engineer has warned ...

There is now a doctrine of what I call “solar triumphalism”: the price of panels has been falling exponentially, the technology makes good practical sense, and only a few further nudges are needed for solar to become a major energy source. Unfortunately, this view seems to be wrong. Solar energy could be a boon to mankind and the environment, but ...