by JG Morgan » Fri Mar 23, 2018 9:20 pm
It's a long time since you asked the question, but as no-one has answered I have consulted Cooke:
Morriston North was renamed Morriston East No 2 - possibly Jan 1950 to match the renaming of the station, but definitely by September 1952. Closed 22 Feb 1965, i.e. about six months before closure of the line north thereof.
Upper Bank Sidings signal box closed 1961 (rather vague). Six Pit Junction signal box closed c June 1961.
Swansea Station (i.e. St Thomas) closed 27 May 1968, the date on which the line to Upper Bank was singled.
I shall look at the Eastern Dock link another time.
Full reference:
Track Layout Diagrams of the GWR and BR WR, Section 53 Swansea Vale Line (Midland Railway), RA Cooke, 1991.