How far away is the existing line from the rear area of Clifton Hospital (the one near to King Edward VII school)?
For the section of the line through Lytham, Ansdell and St Annes, the existing track occupies the Down side of the formation, apart from the section at Skew Bridge/Witch Wood where it was slewed to the middle and raised in the mid-/late-80s...
So from Ansdell to St Annes, the track occupies the same position in relation to the boundary fence on the Down/seaward side as it always has, including the section alongside the rear of Clifton Hospital...
From Ansdell to St Annes the railway has as its seaward neighbour :- Arundel Road, a public footway to the rear of Clifton Hospital, the continuation of the public footway alongside several blocks of post- and pre-war housing, a short section of St Andrews Rd Sth, the backs of traditional Edwardian/Victorian housing...
On the landward side, alongside the golf course, the boundary fence is now pretty much on top of the formation of the former Up track (lifted circa 1984/5 after being disused since the late-70s)...
(The whole 13-mile branch was relaid with cwr/steel sleepers circa 1997, apart from a section about a mile either side of St Annes station, which has cwr/concrete sleepers dating from the late-1960s)...
Despite the encroachments onto the former double-width trackbed either side of Ansdell station, I believe there is still space for a passing loop at Ansdell (though not a longer dynamic loop... and disabled access to Ansdell station would have to be reconfigured, presumably with a lift from Woodlands Road bridge..)...
(Worried that this diversion down the South Fylde Line might be deviating too far from the subject of the thread..!!)..