This"backwater" still carries an hourly service, which means it operates at 2/3 capacity. I would guess it may be something of a timetabling constraint, so there might be a case for a dynamic loop half-way along.Given Scotrail have taken to diverting the Edinburgh to Inverness trains via Stirling, this route seems to be a fair backwater in their operation. I'm not sure it is going to justify doubling in that context.
It was until the 1930s apparently.Was Ladybank to Perth ever double track - certainly the 1957 OS map only shows a short section from Newburgh to Lindores Junction?