Originally Posted by Yanaran

The file that controls those large troop convoys at the start of the war is EastAsiaCampaign.mis in the campaigns folder, and the reason they move at 1 kt is that several of their waypoints are set to 1 kt. Since the waypoints before and after are set to 15 kts, the only reason I can think of is that someone made a typo and like most of the things in the game it was never tested properly.

I've changed all of these in my campaign files to random speeds between 10 and 15 kts.