What is the best way to travel from Tai'an or Taishan train station to Kaifeng on June 24?

It's suggested to go to Kaifeng by taking normal-speed train from Taishan Railway Station because it has more train schedules. They depart from 08:37, 16:42, 17:01, 18:49, 18:55, 22:26 and 23:33. The duration is 6 - 8 hours. The ticket fare of soft sleeper is CNY214, hard sleeper is CNY142 and hard seat is CNY75. :)