I have never played any train sim, but I read video game press that this one hits different.
A lot of train sim are about building the rail network, where Running Train focuses on driving. The scenery (dozens of kilometers of japanese railway) is beautiful and it reproduces the japanese railway system realistically.
Japan has a history of train-driving sims: https://en.wikipedia.org/wiki/Train_simulator#Driving_simula...
Like for some other simulation games, I am impressed how can some go to such lengths to get as close as possible to the real thing but would not actually do it as a job.
Not making fun of it, I just found it fascninating.
I can get it. I can totally see something being fun if it's 2-10 hours a week, but not fun if it's 40-50 hours a week.
Also very different when you are in control of exactly when you're doing it, you can pause anytime you need to go grab laundry, etc.
Driving/train sims have pretty much zero appeal to me, but I enjoy flight sims a fair amount. I'd never want to make the sacrifices to my life that would be required to be a commercial pilot. Being a personal/hobby pilot is very expensive and quite a bit more dangerous.