The Oahu Railway and Land Company at one time had a busy system running from one end to the other of Oahu, and the mainline into Honolulu was double track with block signals.  But after a very busy World War Two period, traffic dropped precipitously as trucks took over the relatively shorthaul traffic on a small island.  The mainline was soon abandoned, but the railroad continued to provide shuttle service between the big canneries in Honolulu and the docks until around 1970.  I visited briefly in 1962 thanks to the U. S. Navy.