Great find Francois! I'm struck by the cleanliness and small size of the stations. I'm guessing this would have been the Eastside IRT--I'm not sure when the westside line from 14th to 42nd was built, but I think it was later than 1905. If that's the case here, the first station north of 14th Street would be the 18th Street one, now closed, that was used as the location for the (original) film 'Taking of Pelham 123'. You can still see it from the train today if you press up against the glass as the train flies by it.