The Create mod allows train tracks to go through Nether portals. This is a very fun feature, that I would really enjoy added to this mod's portals as well. Apologies if this feature already exists, I didn't see anything about it anywhere.

Here's a link to that issue:
#18

I don't think this is really possible as the portals in Wormhole are one-way, so there's no way for me to make sure there's somewhere for the train to go on the other side

That's unfortunate. It would be nice if this was combined with that one request to only allow portals to connect to other portals.