I booked a train ticket in May on the ctrip Chinese site and paid the face value of the ticket: no insurance charge and no credit card surcharge. I paid with a non-Mainland card.

However, you may now have to have a 12306 account to avoid the insurance fee.

Also, I booked using a mobile device, and ctrip may have (may have had) a promotion to waive credit card fees when booking on mobile devices.