If we are talking about short lived spurs, rather than full lines, then there were a few constructed in the West of Scotland to maintain access, mainly to industrial customers when old routes were closed. When the Caledonian route from Glasgow Gentral Low Level was closed in 1964, there was a spur built at Yoker to retain access to Meadowside Granary and Partick Central Coal Depot, opened 29/09/1965, closed 22/03/1980, and at Clydebank for access to Arnott Young Scrapyard, Dewars and an MOD siding, also opened 29/09/1965 and lasted a little longer to 24/04/1988, indeed some of the infrastructure of this spur was still in situ until recently.
In Hamilton, the North British Line had closed to all traffic on 15th September 1952 due to the unsafe condition of the Clyde Viaduct, two spurs came into use on that day, one to retain access to Allenshaw Foundry, this lasted until 09/01/1967, the other went to C&W Irelands Works and was rebuilt on a new formation on 11/02/1963 as further bits of the old NBR line were closed , this became known as the Birdsfield Branch and lasted until 01/04/1980. In Ayrshire, a spur was put in at Stevenson, opened on 27/01/1947 to retain access to Ardrossan Montgomorie Pier when the line through to Neilston was closed, this was in use until 06/05/1968