From #openttdcoop wiki
Moneymaker is the transport infrastructure built during the planning phase of a Public Server game to provide early-game income. Makeshift train networks were mostly used for this traditionally, but have since been replaced by airplanes. An exeption to this is games where the starting date does not allow for planes, making the plane approach impossible.
Moneymaker using trains
In previous games, we booted games using trains. It remains here as documentation for games where the starting year doesn't allow building airplanes.
Moneymaker using airplanes
The new and current approach to boot games in #openttdcoop is to use airplanes. It's the recommended way to boot a game.
In the earlier days of Openttdcoop, unorganized short-term train networks were built as a moneymaker. Coal was typically the cargo of choice because of its tolerability to delays and generally high payment rates. Very few terrain-changes were made and the tracks kept relatively simple to save money. Hubs were typically quick-and-dirty (see Ghetto Style Hubs), and general building codes often overlooked for the sake of simplicity.