Dear Tam Nguye,
Greetings from Sophie, Top China Travel!
Thank you very much for your enquiry about the train tickets between Chengdu and Leshan.
Please kindly be advised that we do book train tickets. However, for this part(short journey) ticket, I suggest you buy it on your own when you arrive in Chengdu. As our company is not in Chengdu, and the train tickets in China are not e-tickets, therefore, we need to handle it through our partner in Chengdu. In this case, the handling fee will too high for a short-distance train.
The train tickets is CNY65 per person for 1st class seat, CNY54 per person for 2nd class seat. While, the handling fee is about CNY 50 per tickets. It is not worth.
I checked that there are 8 trains each day between both cities each day and it needs about 1 hour on the train. And it is easy to buy the tickets one day before the departure date if it is not during national holiday.