If you go into the comment section of that post on TrainSimPlay, you'll find more information about who seems to created it. I'm not going to mention him right here with his forum profile because, I have no clue if it's okay for him as the WIP screenshot has not been shared in his thread yet.
that's Raphael putting his modeling skills into good. He also started doing an ICE 4 (doesnt really mean it will come to TSW in any way though, just maybe): and the ICE 2 again: he said the ICE 2 may be a freeware addition (PC only) and will require the ICE 1 (basically Kassel-Würzburg), but nothing is sure yet. while I wish this was also official, it's good enough already. you can possibly find out more on the Train Sim Community Discord server
It should be a relativey straightforward project, since all that really needs modeling is the cab car. An ICE2 is one-half of an ICE1, literally. A 401 is two power cars with fourteen unpowered coaches in between; a 402 is the same power car with seven of the same coaches, the last with a control cab built into the end.
It really isn't. The powercar required a remodel for example. Cab is different too. Not to mention the differences in the machine room. Regarding the cab car, it's not just a normal coach with a cab, it actually shares the shape of the body shell with the powercar, not with the other coaches.