 Stockholm South station is also connected to the Södra station–Hammarbyhamnen–Stadsgården freight branch line (), which was built between 1925 and 1939 and which formerly provided access to the ports and wharves located at Hammarby and Stadsgården and also provided the only mainline connection with the Saltsjöbanan commuter rail system until 2000.A 550-metre underground spur line also branched off from said freight line to the underground complex at Södersjukhuset hospital (constructed 1937–1944).The Stockholm City Line commuter rail tunnel under central Stockholm opened on 10 July 2017; the section of it under Södermalm starts at Stockholm South Station.