Need Requirements

Been trying to find some Train Sim.

Prefer for my Linux machine
(Athlon 64, 1600MHz, running 32 bit Slackware 14.2, nVidia card Nouveau driver).
I would compile from source code, but the packages I download all seem to be windows binaries.
The Windows and Linux package is still just windows dll and windows binaries.

So, I tried it on an XP machine. All the applications come up as "not a valid win32 application".
The Download page should warn you if this is 64 bit only.
Please put the requirements on the Download page.

I also tried ORTS, which tried to install .NET framework automatically.
Tried it twice but it still cannot find the .NET framework, so I doubt that .NET framework works on this machine.
Is there any way to bypass the compilicated NET stuff, as this machine is off-network almost all the time.
I would prefer to fetch downloads and present them to the program myself.

I do not care for the auto-downloaders as sooner or later they download something broken or incompatible, and then as a user you are screwed, with no path to restore the working setup you had.

It is not 64-bit only (indeed, we're actually stuck on 32-bit due to certain legacy reasona)
All binaries are .Net executables, which work on both Windows & Linux with the appropriate Mono runtime components.

Basic requirements are .Net 4.6 / Mono 5.20.1 & are more fully described here:
https://github.com/leezer3/OpenBVE/blob/master/Building.md#linux

Windows wise, .Net 4.6 requires Windows 7 or newer & the program should automatically handle other libraries. 
Bluntly though,  XP has been end of life for over 6 years & supporting it is not worth time or effort.

Thank you for the answer.
That is deceptive for .NET to be using the .exe suffix for a "something" that is input to another program.

Bluntly, It is XP or Linux. I am not getting any Windows OS ever again. The one Windows 7 machine here is getting switched to Linux. The XP is expressly needed for other reasons, so it will remain here as it is much easier to maintain than Windows 7.

Staying with 32 bit is not a problem. A 32 binary on a 64 bit machine, should run faster than a 64 bit binary on the same machine because smaller ptrs use less cache.

Installing a Microsoft product on my Linux does not feel safe. I suspect this .NET is just a way Microsoft is trying to interpret Windows program I/O. That might work for the typical app, but for a graphics heavy program, this is not good.

I will have to investigate what mono does before I will install such a thing on my system.
I have no desire for any package that is going to automatically install other software.
I have seen that concept break other systems, and my best Linux system is too important to me to allow that kind of risk.

I would rather take the source code and rewrite it to be a true Linux port.
I already have a published game, and we support Linux, BSD, Windows (XP), and some older OS, with few package requirements. It is especailly necessary to use native graphics drawing if the frame rate and frame complexity is at all important.