How much cost for the locker at the Xian train station

As a native of Xian, I can tell you that there is no locker in the railway station. But there is a left luggage site near the entrance of the waiting room, and it is marked in both Chinese and English, you can deposit your luggage there. It is in service for 24 hours, and the fare is CNY 5 for small baggage and CNY 10 for luggage in large size per day.