If you are experiencing problems with Rail Simulator, then the first place that we would recommend checking is the official FAQ which can be downloaded from the Rail Simulator website here (this is a PDF file which requires the free Adobe Acrobat Reader to be installed on your machine).

The FAQ should answer most questions, such as Supported Graphics Cards, how to use the scenario and world editor tools, error messages and all of the main questions which the Rail Simulator team are asked.