It takes 3.5 hours by bullet train from Beijing West Railway Station to Taiyuan. Then take a taxi to Jiannan Bus Station. There are many buses to Pingyao. It need another two hours. Or you can buy train ticket at Taiyuan Railway Station and get into the railway station to take train to Pingyao. There are many trains everyday and it is easier and safer than taking a bus. You can think of taking an ordinary train from Beijing West to Pingyao directly. The train leaves at night at arrive in Pingyao next day morning. Although it takes 12 hours, but it save time at daytime and money, and easist.