Locate the file named config.script in the folder My Documents/Cities in
Motion/. Open the file in Notepad and look for line:

$debug = false;

Change it to:

$debug = true;

Then add at the end of chapter line:

$disableDebug = false;

You may now use the following cheat keys in the game:
Code:....    Result:
[F1].....    Skip Day
[F2].....    Force Objectives Completion
[F3].....    Add 10.000 Money
[F4].....    Skip Passengers (in Objectives)
[F12]....    Open Console