Waiting for a North London train a couple of days ago the station person
(what are they called these days?) came down onto the platform carrying what
looked like a mobile phone. He went behind the side of the shelter and
appeared to hold the "mobile phone" to the fence (the fence was creosoted a
very dark colour). He appeared to do the same thing in more than one place
on both platforms. When I looked there was a black "stud" (only word I can
think of) which was simply inserted into the fence panel - it wasn't a
fastener, there was not a post or anything behind the panel.

Is there any significance to his actions?