Okay, here's what's up.
The game works on XP -- you can even set the game speed, in settings.
What it does, is it has its own DOSBOX emulator (actually, version DOSBOX .065) built into it so it runs. They worked w/ DOSBOX's makers to get it going, which it says in the README.
Here's the README:
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Sid Meier's Railroad Tycoon Deluxe
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README
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INDEX
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1) NOTES ABOUT DOS COMPATIBILITY
2) PERFORMANCE ISSUES
3) COPY PROTECTION
4) SOUND EMULATION
5) CREDITS
6) SPECIAL THANKS
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1) NOTES ABOUT DOS COMPATIBILITY
Railroad Tycoon Deluxe is a DOS based game. For this release we have included DOSBox, a DOS emulator to maximize compatibility. DOSBox is an open source project and is not supported by 2K Games or Take-Two Interactive. For issues related to DOSBox please contact the DOSBox team, or use the support pages at http://dosbox.sourceforge.net/.
This installation includes DOSBox 0.65. This is an unmodified installation, and the source code can be downloaded on the DOSBox site (URL above, or in the "Web links" folder on your start menu).
2) PERFORMANCE ISSUES
When you install Railroad Tycoon using the included installer, it will create two shortcut files on your start menu: one for full screen and one for windowed mode. Railroad Tycoon is a very old game, and running it in full screen mode may cause visual artifacts or glitches depending on your computer's resolution (this is particularly likely on LCD monitors). For the best overall compatibility, run it in windowed mode. You can also hit ALT+Enter while in-game to switch between the two.
Note that when playing in Windowed mode, DOSBox will lock the mouse to its window. To get external control of the mouse back, you can either ALT+TAB to a different window, or hit CTRL+F10.
If you notice performance issues (such as the game running too fast or too slow) you can throttle the emulated speed by hitting CTRL+F12 to speed it up, or CTRL+F11 to slow it down.
Note that because we have included a full DOSBox installation, you can also modify the settings however you like. To do that, edit the dosbox.conf file in the DOSBox folder of your installation directory. For information on the various options, visit the DOSBox web site. Also visit VOGONS (http://vogons.zetafleet.com/) for discussion on getting older games to run on modern systems.
3) COPY PROTECTION
Railroad Tycoon Deluxe utilizes a manual-based copy protection system. This was common back when Microprose first released Railroad Tycoon. The game asks the user a question, which can only be answered by checking the physical manual. For this release we have provided the complete Railroad Tycoon Deluxe manual in PDF format, as well as a quick reference sheet that has all the trains you'll need to answer the copy protection answer. We recommend that you print out this sheet and keep it handy when playing the game, or switch to windowed mode (if you're running full screen it's ALT+ENTER) and open the manual or reference sheet in another window. You will have to do this every time you run the game. You can find both PDF files in the manual folder in your install directory, and shortcuts to each were created in your start menu during the installation process.
4) SOUND EMULATION
By default, DOSBox and Railroad Tycoon are set to use straight MIDI for music and Soundblaster Pro for digital speech. In the event that you do not hear any music, this means you either have MIDI sound turned off or at a very low volume (change this by going to your sound mixer control panel) or have an on-board sound card that does not support MIDI at all. You can change RRT's audio settings by running the "Modify Audio Settings.bat" file in your RRT install directory. This will launch DOSBox and load up the RRT setup app. After skipping the readme section, select "Reconfigure Hardware Options" and change it from "General MIDI" to "Soundblaster Pro (later)". Hit enter several times and leave everything else the way it is. You should now hear emulated MIDI music the next time you run the game.
5) CREDITS
ORIGINAL MICROPROSE TEAM:
Original Game Design:
Sid Meier with Bruce C. Shelley
Additional Design:
Christopher B. Hewish
Programming:
Jeff Billings, Shizuka Takahashi, John Taylor
Graphics:
Mark Glidden, K.K. Dembeck, Max Remington III, Murray Taylor,Rawn Martin
Sound Effects:
Jim McConkey & Scott Patterson
Music:
Jeffery L. Briggs
6) SPECIAL THANKS
The DOSBox developers and beta team at VOGONS for all of their help.