Queensland Railways 3900 class

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

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

{{Infobox locomotive

|name = Queensland Rail 3900 class

|powertype = Electric

|image = QR electric loco 3917 and another haul a northbound goods train on the NCL with Mt Tibrogargan in the background.jpg

|alt =

|caption = 3917 and another haul a northbound freight train on the North Coast line in 1989.

|builder = Walkers Limited, Maryborough

|ordernumber =

|serialnumber =

|buildmodel = JA39-3B

|builddate = 1988–1990

|totalproduction = 30

|rebuilder =

|rebuilddate =

|numberrebuilt = 19

|aarwheels =

|uicclass = Bo-Bo-Bo

|gauge = {{RailGauge|1067mm}}

|trucks =

|bogies =

|wheeldiameter =

|trailingdiameter =

|minimumcurve =

|wheelbase =

|length = {{convert|20.02|m|ftin|abbr=on}}

|width = {{convert|2.8|m|ftin|abbr=on}}

|height = {{convert|3.89|m|ftin|abbr=on}}

|frametype =

|axleload =

|weightondrivers =

|locoweight = {{convert|109.8|t|abbr=on}}

|sandcap =

|powersupply =

|electricsystem = 25 kV AC overhead lines

|collectionmethod = Pantograph

|alternator =

|generator =

|tractionmotors = ASEA

|headendpower =

|transmission =

|multipleworking =

|maxspeed = {{convert|100|km/h|abbr=on}}

|poweroutput =

|tractiveeffort = {{convert|2890|kW|abbr=on}}

|factorofadhesion =

|trainheating =

|locobrakes =

|locobrakeforce =

|trainbrakes = Davies & Metcalfe P85

|safety =

|operator = Queensland Rail

|operatorclass = 3900

|powerclass =

|numinclass = 30

|fleetnumbers = 3901–3930

|officialname =

|nicknames =

|axleloadclass =

|locale =

|deliverydate = 1988

|firstrundate =

|lastrundate =

|retiredate =

|withdrawndate =

|preservedunits =

|restoredate =

|scrapdate =

|currentowner = Aurizon

|disposition =

}}

The 3900 class are a class of electric locomotives built by Walkers Limited, Maryborough for Queensland Rail between 1988 and 1990.