FAQ
OpenTTD Manual
Installation · FAQ
Tutorials and Instructions
Game interface · README.md
Infrastructure

Railways:

Signals · Stations · Junctions · Carrying capacity · Rail Designs & Tips
Roadways · Tramways · Waterways · Airports · Landscaping
Vehicles
Trains · Road vehicles · Ships · Aircraft · Orders
Settings
Game options · Settings · AI settings · Custom graphics (NewGRF) · Cheats · Command line
Graphics and sound
OpenGFX · OpenMSX · OpenSFX
More topics
Climates · Towns · Industries · Economy · Disasters · Tips · Hidden features · Hotkeys · Console · Game Mechanics · Multiplayer · Scenario editor · Online content
Troubleshooting · Links

There are several FAQ categories available: