Get yourself a dedicated harddrive @Bertobaby99, for your Trainz install. Preferably an NVME mounted SSD, or regular SSD, or if you can't do that, a fast Western Digital Black 4-6 gig harddrive.
Some good deals on Amazon. Your motherboard will need to be able to support SATA III (6Gb/s) transfer speeds for the WD Black, or have an NVME slot for the SSD.