Good Afternoon Alco_P-A
As you purchased these through the 'shipping only' option, your boxed editions will not include any serial numbers, as these are only required for registering Trainz to your account; they are not required for installation of Trainz. The 'shipping only' option is provided to allow upgrading a digital download purchase to a boxed edition purchase, and as such Trainz will already be registered to your account in this situation.
Regards