Advanced railway reservations for busy travel times?

We are planning to travel in china during a very busy time around chinese new years. Is there any way to get railway reservations more than the usual 12 days in advance? We would much prefer to travel by rail, but cannot risk being unable to travel. Otherwise we will need to make airline reservations because they allow reservations in advance.

On our last china trip we only barely got a seat on a train, and that was at 4am.