Leaving from Changchun to Beijing via train with 2 luggages, can i post them by train to Beijing?

my flight leaves Beijing capital airport but i would prefer to send my suitcases to beijing prior to me getting there by train. When i get to beijing i can collect them and head to the airport. I have heard that this service exist but can not get any information on where i should go, where to collect them in Beijing and the cost of this service. grateful for any advice.