A train, which carries 20,000 metric tons of coal, runs on the Shuozhou-Huanghua Railway. SHI JIAMIN/FOR CHINA DAILY Locoman Sun Dongsheng is extremely cautious every time he drives a heavy-load train ...

Weight translates to money when it comes to the airline industry. Every additional pound requires more fuel to lift, so making sure there is sufficient gas in the tanks means knowing what the aircraft ...