The location was just below ally pally. A public footpath on the embankment allowed observation of railway activity from above. The position and height was approx. level with the rather large signal gantry. There was a branch line heading westwards where a GWR 1500 would appear with a few waggons. The signal gantry gave early warning of loco movements, a chime whistle the group would utter “streak” in unison. From memory the track plan was between 15 to 20 tracks wide thus there was a lot going on. Much better than Finsbury park where one had to squeeze behind the tennis courts to be a good view of the railway.
Not been there for 70 plus years……..probably changed a bit since then?
Bigj