Hi we intend to take a train to Pingyao from Beijing Railway Station on Apr 12.

Do you refer to the luggage storage facilities at BJ Railway Station? If yes, don't worry. You can easily find the Electronic Locker and ordinary left luggage counter. For one piece of luggage, I remember that the fares are CNY 15/7 hours for electronic ones and CNY 10-30/per day for left luggage counter.