Is it possible to transfer entire trains between the Overworld and the Nether? When I tried, just the loco warped to the Nether, leaving the rest of the train in the Overworld, which is annoying, having to decouple the entire train and push each cart by hand manually to the other side and rearm the train again in the Nether. Also, when I push a single cart to the portal, it appears derailed in the other side, like it is avoiding the tracks (looking them as a not suitable destination block).

Not without writing my own portal or doing some core modding.