It wouldn't surprise me if Japan has its own market for train assets. There's a big community of train simulators! Go to the Kyoto or Tokyo train museums, they have dozens where you step into a replica of a train cab and then drive a photorealistic simulation (sometimes also just film) - the ex-keyboarder for Casiopeia runs a train simulation game company that makes those since the 90s (https://en.wikipedia.org/wiki/Minoru_Mukaiya). There are some Nintendo Switch train simulators like Densha de GO that are only available in Japan.

I'm sure there's a treasure trove of already-built high-quality assets of Japanese trains.