At what resolution, with what CPU, in window, or full screen? Too many parameters to say, but the game isn't supported on laptops anyway, though it does run at low level graphics quite well for the most part
4 GB is not enough. I have been running routes with RAM usage of almost 4.8 GB. you will still need enough RAM to run your system at the same time. I would suggest 8 GB minimum but the rest of your system must also meet minimum specifications.
I've played 551 hours on 4Gb or less. A surface pro 4 laptop and a desktop PC both running windows 10
I have TS installed on a laptop with 3GB and ye bog-standard integrated graphics more as an experiment than any other purpose. It's pretty flakey as you might expect but it does work with some caveats: forget steam engines; forget routes with a lot of detail (including catenary); don't expect scenarios with lots of DLC dependencies to work; most of the graphics setting are on the peg. With an old route such as Settle-Carlisle which is largely rural and thus undemanding scenically it's adequate. If I didn't have other options I'd put up with it but I'm glad I don't have to.
