Lovely video and just as lovely a hooter. It's not an N&W whistle though. The shape of the bowl and the domed bell tell me that it's a Lunkenheimer hooter. Not the first time I've seen a Lunkenheimer hooter sound like an N&W hooter.
Hey, when I got a closer look at the hooter whistle, I realized that's not the one made by the N&W, because the top is not flat and the bowl doesn't resemble the other N&W Hooters. Because that it has a round top and a rounder bowl, I think that could a Lunkenheimer hooter whistle. But hey, at least it sounds just like it!