Mmmm... Difficult to describe without a pic/scan (can do neither sorry) but.... From a bird's eye view over the whole station, from north to south you had:-
Stabling siding (no platform access) Loop siding accessed from platform Main line to H.Square accessed from platform Main line from H.Square accessed from platform Loop siding accessed from platform. Stabling siding (no platform access.)
Soooooo.. you had six parallel tracks in total. This was c1968. Info from:- Mersey Railway Electric Stock. Signal Transport Papers. by Cull & Prigmore. 1968
This is the track layout through Birkenhead Park Station in the 1940s, which is as Pinzgauer described, it remained similar to this until the 1970s when the layout was changed several times, ending up with a single, widened island platform with just two tracks by the 1990s.
Just one other question on this area- coming back from Conway Park, just before exiting the tunnel, I noticed what looked like a disused spur going off to the right- has anyone any information on this
The disused spur you noticed was provided when the line opened as the starting point of a projected link to the docks.
The plan was for goods to be taken across the river. What is now the start of the new Loop line before James Street station was to have been the start of the connection to the dock lines in Liverpool. There is another "blind" tunnel on the Birkenhead bound side of the tunnel at this point which was part of the same scheme.
It was calculated that the maximum loading of freight trains would have been too little to be economic so the plan was dropped.