Cambridge railway station has 4 platforms and direct links to London King's Cross. Some trains go direct, others may stop at all or some of the following:
A direct train leaving later than a train with several stops often arrives quicker, so if you are in a hurry take note of how many stops there are.
Cambridge also has a number of other lines in operation:
Fen Line: To Kings Lynn and Ely.
Breckland Line: To Norwich.