Not exactly a brilliant picture this one but to be fair my brother was on board a train when he snapped it.
It was taken in the early 70's around the area between the rail bridge and the station.
To get technical for a moment - the WHISTLE sign was to warn of an approaching train shunting in the wrong direction over the up line.
The 2 signal arms on the tall post are shunting signals controlling one of the entrances to the goods yard.
What amuses me about the photo though is the reminder that back in the 70's my brother used to show his photos using a slide projector & screen at home, and every time this photo popped up on view, everyone in the room started to whistle!
You should recognise the view taken from the end of the platform.
The image was shot in December 1983, a year before these semaphore signals were replaced with a new coloured lighting system.
The signal boxes in the background are West Box & Central Box.
The "Push-Pull" train in the picture is another piece of history, and I'm pretty certain it has ScotRail on the side too!
If you need to delve deeper into the images, click onto them for the large versions.