We can finally release details about Rail Simulators hardware requirements, so here they are:

In order to install and play Rail Simulator, your system must meet or exceed the following minimum system requirements
Operating System: Windows XP with latest service pack installed / Windows Vista
CPU: XP - Intel Pentium 4/AMD Athlon 1.7 GHz or equivalent; Vista - Intel Pentium 4/AMD Athlon 2.6 GHz or equivalent
RAM: 512 MB
Video Card: 64MB DirectX 9.0c compliant video card, Pixel shader 2.0 and above. (AGP and PCIe only)
Sound Card: - DirectX 9.0c compatible
Hard Drive Space: 4.5 GB of space is required to install the game

In order to play the game as intended, your computer should match or exceed the following recommended system specifications:
Operating system: Windows XP with latest service pack installed / Windows Vista
CPU: Intel Pentium 4/AMD Athlon 3.0 GHz or equivalent
RAM: 1.0GB
Video Card: 256MB DirectX 9.0c compliant video card, Pixel shader 3.0 and above. (AGP and PCIe only)
Sound card: Sound Blasterî X-Fi™ series from Creative Labs
Hard Drive space: 4.5 GB of space is required to install the game