Baggeage Checking on G-Trains

Hi, we are considering travel from Beijing to Xian by G-Train. We will have large luggage. We know that these large bags are not allowed on the G-Train. We have read on this site that there is no consignment on the G-Trains, either. So, can we "check" the bags and will they arrive in Xian about the same time that we do? If the bags cannot travel in the same train as we do, then how do they travel, by T- or K-Train?