This is nothing more than a reboxing of their 1/72 Morser Karl kit (82905 if it's the late version as it appears in the CAD, or maybe it has both versions, early and late) with the railcar kit (82906). All these kits are from 2007-2008, they're just bundled together now.
I've built them back then and they were a very decent kit. Basically the scaled-down version of the Trumpeter kits.