A station can be termed as a junction, even when there are no interchangeability of routes.
CLA (Kurla is designated as junction - even though it has 2 different lines that branch out from the either ends and there are no connections between these 2 lines.
Further,...
more... there are(were) stations that were classified as Jn even though the branch lines are of different gauges. Stations like MRJ, KWV, GTL, SBC, PGT were designated as Junction even though at one point of time - the branch lines were of different gauges.
There is actually a grey area when it comes to nomenclature of stations as junctions - stations like BSR, PNQ, ERN, NDLS arent named as Jn even though there are branch lines from these stations.