Hi,
Remember that TS19 and TANE use the GPU more than CPU!
I'm using an i5 (overcooked to 4.2) with an nVidia 2060. That's capable of >30fps with settings high to ultra +shadows.
Both CPU & GPU are about 95% capacity.
I would suggest the best CPU you can afford, GPU better than 2080, and a separate fast see for the Trainz programs & data.
Make sure that your pc case has good cooling, and I'd recommend a high-end cooling for the CPU not the standard fan.
As always, the performance will depend on the route. A large route with lots of details will be slower than a small route with only a few details.
Colin