In order for you to play Sid Meier's Railroads! on Windows with minimal graphics settings, your computer must meet the following requirements
Windows 2000, Windows XP
1.4GHz Intel Pentium 4 or AMD Athlon processor or equivalent
512 MB RAM
64 MB Video card with hardware pixel and vertex shaders (GeForce 3, Radeon 8500 or better)
DirectX 7 compatible sound card
1.7 GB of free disc drive space
In order to play Sid Meier's Railroads! on Windows with maximum graphics settings, you need a computer with a configuration no worse than the following
Windows 2000, Windows XP
2.0 GHz Intel Pentium 4 or AMD Athlon processor or equivalent (or better)
1GB RAM
128MB videocard with pixel shader 2.0 support (Radeon x800, GeForce 6800)
DirectX 7 compatible sound card
1.7 GB of free disc drive space