 Complete the following phrase:  Until the interchange station at South Acton was opened on 1 January 1880, the branch line to Hammersmith  Chiswick employed an unusual mode of operation. Southbound NLR trains to Kew which was on the western chord to the Hounslow Loop near the current Kew Bridge station included a carriage for passengers travelling to Hammersmith  Chiswick. This carriage was uncoupled from the rest of the train immediately south of the junction. The NSWJRs sole locomotive would then reverse onto the mainline, be attached to the carriage, and take it down the short branch to Hammersmith  Chiswick. From 1 January 1880, on the station opening at South Acton, passengers could change there from 