Original soundtrack composed by: John Broomhall
Now here's one that you can whistle to: "Sawyer's Tune". Not sure why the track is called "Sawyer's Tune" unless it's simply a tribute to the game's creator, Chris Sawyer. But just in case it's about the profession, here's a screenshot of a sawmill.
The music was recorded through DOSBOX after selecting the AdLib/Soundblaster FM option in the configuration utility (which is apparently OPL2 emulation).
[ VIDEO: Choicest VGM - VGM #279 - Transport Tycoon - Sawyer's Tune ]