The EMD F3 is a 1,500-horsepower (1,100 kW) B-B freight- and passenger-hauling carbody diesel locomotive produced between July 1945 and February 1949 by General Motors’ Electro-Motive Division.

Some late-model F3's had the same D27 traction motors, along with the heavier-duty electrical cables, used in the F7, and were referred to as model F5 by EMD's Engineering Department.

Phase I is similar to the F2, distinguished by three portholes on the side and "chicken wire" grilles along the top edge of the carbody.

The primary changes were threefold: mechanical reorganization of the interior to permit faster construction, an improved prime mover developing 1,500 hp (1.1 MW) instead of 1,350 hp (1.01 MW), and a new main generator (the D12) to handle the increased power output.

[7] After problems developed with the first set of demonstration locomotives, EMD introduced a modified design called the F2 using the generator (D4) from the FT.

[10] The Missouri–Kansas–Texas Railroad conducted extensive trials with EMD's demonstration unit against its own 2-8-2 locomotives, following which it ordered 21 F3s.