Railroad Tycoon 1.06

[pakrat2k2]

on steam forum.... user posted how to get it to work

The 1.06 patch won't install over the steam version, because it uses a different .exe (one that doesn't check for a cd)
If you reinstall the official 1.05 patch over the steam version, the 1.06 patch will install but the game will ask you to insert a cd.

You should be able to fix this by getting the 1.05 cracked exe and installing the 1.06 patch over it. The game should run fine that way.
But before you do that, check if it's legal where you live. In some countries it's illegal to crack a game even if you own it.

[tycoonjeff]

That's what I've done previously on XP and 7 machines (not sure if the OS matters but now I'm on 8.1, and that's the only difference I can think of.)

This time attempting to install the 1.06 patch over the cracked 1.05 exe produces an error (when it didn't on the XP and 7 machines.) After much frustration with uninstall and reinstall and try again, I wondered if it would be possible to just crack the 1.06 exe (yes the 1.06 patch installs fine over an un-cracked 1.05 exe for me still on 8.1.)

Honestly, I was hoping there was a tool that could handle old protections like this CD check, but it appears that cracking must be done manually and requires skills I don't have.