The RailSimulator_Demo.exe file you have requested: Official Demos / Rail Simulator Demo - 471.22mb is not available. Upload any files you want to share. This is the only information we could locate:
The demo features a Black 5 running out of Bath Green Park, heading to Radstock and provides tutorial dialogs to help you along the way. The demo cuts out after 10 mins or so and allows you to restart.