As a test project, I thought I'd try to make it so that the Horse resource required a road before you had access to Horses. I have been able to alter the tile yield based upon the presence of a road. There is a table called "Improvement_RouteYieldChanges" which has this effect. I verified this functionality using the following code: Spoiler : Code: <GameData> <Improvement_RouteYieldChanges> <Row> <ImprovementType>IMPROVEMENT_FARM</ImprovementType> <RouteType>ROUTE_ROAD</RouteType> <YieldType>YIELD_GOLD</YieldType> <Yield>10</Yield> </Row> <Row> <ImprovementType>IMPROVEMENT_TRADING_POST</ImprovementType> <RouteType>ROUTE_ROAD</RouteType> <YieldType>YIELD_SCIENCE</YieldType> <Yield>1</Yield> </Row> </Improvement_RouteYieldChanges> </GameData> Using this code, a farm does yield an extra 10 gold after a road is placed to it, and the trading post does yield the extra science when it has a route. However, I can't see any table which might alter the access to the strategic resource based upon a road to the improvement which accesses the strategic resource. The only thing I can change based upon roads are tile yields (eg. gold, production, etc.), and not strategic resource yields (horse, iron etc) Can anyone help?