Railway Forum - Gift for my grandfather

Hi all,

My grandfather had a stroke a few years back, and his mental capabilities, especially speech, have been declining ever since. He lives with my parents and my 4 (much) younger siblings - the house is always chaotic and no one has time to talk to him much. I think a lot of his trouble comes from being "checked out" because of that. He loves trains, and used to have the best model railroad in our city. (as far as I'm aware) Schools took field trips to visit his house and see the layout. He had to sell EVERYTHING when he moved in with my parents. It was very sad.

All that to say, I would love to get him something for Christmas that could reignite that interest and give him something to mentally engage with when the family is too busy to talk with him. They have a fairly old Windows 7 PC, so it would have to be easy on the hardware. (though I can afford a few hundred for a newer PC if need be) It would also need to be very simple. He hasn't lost his reasoning abilities, but he has trouble communicating and was never very computer-literate. Something a kid could figure out on his own would be good.

Can anyone recommend some software/game to me for this? I've looked around, but everything I've seen so far has been either so complicated that I barely understand it, too old to run on a modern PC, or doesn't allow you any freedom to build what you want.

Thank you for taking the time to read/reply.