The downloads include both the usual version and the LAA version and you choose between them in the Options form. Fortunately it is possible to compile a program, for 64-bit systems only, which can use up to 4GB of memory and this is called a Large Address Aware (LAA) option.
Many current PCs, especially 64-bit systems, have more than this. Programs compiled for 32-bit Windows are always limited to using a maximum of 2GB of memory. When run on a 64-bit Windows system there are some benefits as follows. Open Rails is currently a 32-bit program that will run on either 32-bit Windows or 64-bit Windows.
* Windows 7 requires Service Pack 1 (SP1). It does not work on Windows XBox, Windows Phone or non-Windows platforms. Open Rails works well on Windows PCs from Windows 7* onwards (including Windows 11). Installation Questions from the FAQ Which platforms does Open Rails run on?
