Queensland Railways 1720 class

{{Short description|Class of Australian Co′Co′ diesel-electric locomotives}}

{{Use Australian English|date=June 2020}}

{{Use dmy dates|date=August 2019}}

{{Infobox locomotive

|name = Queensland Railways 1720 class

|powertype = Diesel-electric

|image = 1723_Bi-Centennial_Livery_-_040288_-_Moolabin.jpeg

|alt =

|caption = Bicentennial liveried 1723 at Moolabin Yard railway station in February 1988

|builder = Clyde Engineering, Eagle Farm

|ordernumber =

|serialnumber =

|buildmodel = Electro-Motive Diesel GL18C

|builddate = 1966–1970

|totalproduction = 56

|rebuilder =

|rebuilddate =

|numberrebuilt =

|aarwheels = C-C

|uicclass = Co′Co′

|gauge = {{RailGauge|1067mm}}

|trucks =

|bogies =

|wheeldiameter =

|trailingdiameter =

|minimumcurve =

|wheelbase =

|length = {{convert|13.4|m|ft}}

|width =

|height =

|axleload =

|weightondrivers =

|locoweight = {{convert|62|t}}§

|fueltype = Diesel

|fuelcap =

|lubecap =

|coolantcap =

|watercap =

|sandcap =

|powersupply =

|consumption =

|watercons =

|primemover = Electro-Motive Diesel 645E

|rpmrange =

|enginetype =

|aspiration =

|displacement =

|alternator =

|generator = Electro-Motive Diesel D25

|tractionmotors = Electro-Motive Diesel CD36

|headendpower =

|cylindercount = 8

|cylindersize =

|transmission =

|multipleworking =

|maxspeed = {{convert|100|km/h|mph}}

|poweroutput = {{convert|745|kW|hp}}

|tractiveeffort =

|factorofadhesion =

|trainheating =

|locobrakes =

|locobrakeforce =

|trainbrakes =

|safety =

|operator = Queensland Railways

|operatorclass =

|powerclass =

|numinclass = 56

|fleetnumbers = 1720–1775

|officialname =

|nicknames =

|axleloadclass =

|locale =

|deliverydate =

|firstrundate = October 1966

|lastrundate =

|retiredate =

|withdrawndate =

|preservedunits =

|restoredate =

|scrapdate =

|currentowner = Aurizon, Queensland Rail

|disposition = 33 in service, 10 stored, 12 exported, 1 preserved

}}

{{Listen| align=right |filename = Queensland Rail 1738 - 2018-09-08 - Andy Mabbett.ogg|title = Locomotive 1738 idling at Roma Street railway station, while waiting to depart with a long-distance passenger train |description = recorded 8 September 2018 }}

The 1720 class are a class of diesel locomotives built between 1966 and 1970 by Clyde Engineering, Eagle Farm for Queensland Railways in Australia.