We have done loads of train trips, maybe not quite as long, usually like an hour? And we also took our daughter on a plane, which again was maybe an hour or so, but closer to 2 hours if you factor in sitting around on the ground. But I think it's definitely doable. Just pack really smartly. Bring a rucksack or something you can carry really easily without needing your hands. If you have a carrier or wrap rather than a pushchair, that also helps (or if you can avoid bringing a pushchair altogether). I found the hardest thing about train travel is struggling to get the pushchair in and out and then folding it up to stow away while keeping my kid from running off somewhere. It was much easier when we took a carrier or when I just carried her or made her walk (maybe not as easy with a younger one though). Then bring toys and snacks and some milk and anything else he enjoys. If you can plan it for naptime and then just lie him on you and have him sleep, that might be the easiest way to do it. But my daughter has always been really entertained by trains, loves to look out the window, will sit and read books with me, will spend time snacking, etc. It's really always been fine. If you can travel at a time it's not super busy and make sure you get a seat (with Virgin you can reserve, right?), then that's ideal too.