Boring technical background:

The 3GB enabler is of script popular for games from the ~2006 era. This point in time marked a transition point as games ram requirements expanded to around 2GiB, a key limitation in 32bit Windows.  In 32bit systems the maximum amount of processor addressable space is 4GiB. In early 32bit versions of windows this space is split equally with Windows getting %50 and everything else getting the remaining %50. As applications started becoming larger Microsoft made the limit more flexible giving Windows a smaller portion of the pie. Unfortunately this is not as simple as it should have been since many Windows Applications relied on this 2GiB cap. In order to maintain support for these programs Microsoft added a special value that programs could use to tell Windows that it is okay to give said program more than 2GiB. What the 3GB Enabler does is add this special value to SMR’s railroads.exe which tells Windows to allow railroads.exe to use upto 4GiB of RAM.

Real Introduction:

Now this explanation is rather complex and might not interest you, the handsome, pragmatic user, who simply wants to play those large, awesome, custom maps available for download in the Map Database. Fear not for I bring you a Simple! step by step guide complete with conditionals and my vain attempts at humor (Yes that is correct, I am not above self-deprecation).

Step 0:

Does your computer only have 2GB or RAM? Does your video card have ~2GB or RAM? Is SMR crashing with the stock maps? If you said yes to any of these questions the 3Gb enabler cannot help you. I’m sorry but in order to enable more RAM you at least  need to have this more RAM stuff. In the case of high end video cards much of the extra space in 32bit address limit is being used up by the video card’s RAM. Lastly if SMR is failing to play the original maps this is indicates that some other bug is present. You will not suffer any negative effects from the 3Gb Enabler but it does not bring any benifit.

Step 1:

Check if you have a 32bit or 64bit version of Windows, instructions courtesy of Microsoft:

To find out if your computer is running 32-bit or 64-bit Windows, do the following:

  1. Open System by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking System.
  2. Under System, you can view the system type.

Step 2:

If you have a 32bit version of Windows XP you must do this:
Manually edit your boot.ini file by adding ” /3GB /Userva=2900″ to your boot.ini (no quotes). Your boot.ini is normally read only and you will need to change that temporarily while you edit it. To do this, right-click the file and untick “Read Only”. After editing the file, restore the Read-only status. To Edit it manually you can find it on the root of your system drive or go to system properties/advanced tab, settings under ‘startup and recovery’ section, then hit edit. Mine looks like:  multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=”Windows XP Professional” /FASTDETECT /NOEXECUTE=OPTIN /3GB /Userva=2900

Step 3:

If you have a 32bit version of Windows Vista or Windows 7 you must:
Go to the start menu and in the search box type ‘cmd’, don’t hit enter. Wait until ‘cmd.exe.’ appears on the menu and then right click and select “run as administrator”. Then run this command:  BCDEDIT.EXE /Set IncreaseUserVa 2900

Step 4:

Download this zip containing the 3GB Enabler script:  This link, right here. Or download the pre-patched exe and replace the normal Railroads.exe, you may skip to step 5.5 then be done.

Step 5:

Extract the 3GB Enabler into the Sid Meier’s Railroad’s Program Files drictory. On 32bit versions of Windows this will be found at C:\Program Files\2K Games\Firaxis Games\Sid Meier’s Railroads!  In 64bit Windows: C:\Program Files (x86)\2K Games\Firaxis Games\Sid Meier’s Railroads!

Step 5.5:

If you have not already patched SMR to version 1.10 now is the time to do so. Without the 1.10 patch most custom maps will not work and many original maps will randomly crash. The SMR 1.10 patch can be found at Fraxis’ site: www.firaxis.com/games/game_detail.php?gameid=12&showcon=2

Step 6:

Inside the SMR Program files folder will be the files you extracted in step 5. One of these files is “startme.bat”, double click on this program to run it.

Step 6.1:

Hit the A key to add the large address header. Press any key to continue. You are now down and may close the window, or optional complete the next two steps to verify that the patch worked.
Optional Step 6.2: When back at the main menu hit ‘V’ to output the headers in text so you can see the values. Optional Step 6.4: Now you can check to see if the patch is enabled.  Scroll to the top and look for the section “FILE HEADER VALUES”. Look for a line in that section that says “Application can handle large (>2GB) addresses”.  It’s the tenth line down in that section.  If you see that line then the executable is now enabled for >2GB, you are done.