Solution.sql

;WITH cte AS 
(
SELECT StationName , 
       StationPhysicalOrder
FROM Stations 
WHERE StationPhysicalOrder = (SELECT MIN(StationPhysicalOrder) FROM Stations)
UNION ALL 
SELECT COALESCE(StOverride.StationToName, Stations.StationName) AS StationName  , 
       COALESCE(StOverride.StationPhysicalOrder, Stations.StationPhysicalOrder) AS StationPhysicalOrder
FROM Stations 
JOIN cte 
ON Stations.StationPhysicalOrder = cte.StationPhysicalOrder + 1 
OUTER APPLY
	(
	SELECT StationRoutingOverride.StationToName, StationOverride.StationPhysicalOrder
	FROM  StationRoutingOverride
	JOIN Stations AS StationOverride 
	ON StationOverride.StationName = StationRoutingOverride.StationToName
	WHERE StationFromName = cte.StationName	
	) StOverride
)
SELECT StationName
FROM cte