The NS 3600 was a series of express steam locomotives of the Dutch Railways (NS) and its predecessors Maatschappij tot Exploitatie van Staatsspoorwegen (SS) and Nederlandsche Centraal-Spoorweg-Maatschappij (NCS).

73–78 did not have a fully streamlined cab, and 75–78 also had slightly different tenders.

Because of their conical shaped smokebox door, these locomotives soon got the nickname "Zeppelins".

In 1925, these locomotives were rebuilt with a boiler that was practically the same as that of the series NS 3700, because of the wider Belpaire firebox the cab lost its streamlined shape.

In 1935 the locomotives had brakes fitted on the bogie, and they received a fully welded tender that had the same water and coal capacity as the tender of the series NS 3900.