| Sri Lanka Railway M6 | |
| Powertype: | Diesel-electric |
| Builder: | Thyssen-Henschel under licence from Electro-Motive Division |
| Serialnumber: | 32337–32352 |
| Totalproduction: | 16 (14 in use) |
| Uicclass: | A1A-A1A |
| Wheeldiameter: | 10160NaN0 |
| Trailingdiameter: | 8380NaN0 |
| Length: | 54feet |
| Width: | 3090abbr=onNaNabbr=on |
| Height: | 4113abbr=onNaNabbr=on |
| Axleload: | 16.7t |
| Locoweight: | 87t |
| Primemover: | EMD 645E |
| Cylindercount: | 12 |
| Maxspeed: | 96.6km/h |
| Poweroutput: | 1650hp |
| Tractiveeffort: | (ù=0.3) 193kN |
| Locobrakes: | Vacuum, Dynamic |
| Operator: | Sri Lanka Railways |
| Fleetnumbers: | 783 to 798 |
| Firstrundate: | 1979 september |
| Disposition: | Still in service |
| Notes: | Standard livery: green, red and yellow stripes ICE livery: red and orange on loco numbers 785, 788, 797.792 also was in ICE livery in the 1990s, now standard livery. |
Sri Lanka Railways M6 is a class of 16 Diesel-electric locomotives imported to Sri Lanka in 1979. Manufactured by Thyssen-Henschel in Kassel, West Germany, under licence from Electro-Motive Division of the United States. As an EMD G22M, it has a V12 EMD 645 engine rated at 16500NaN0. Most are still in service. Very successful in upcountry line, since it has Flexicoil truck (bogies) and dynamic brakes. Loco numbers 793 and 798 engines were destroyed by LTTE terrorists. M6 790 (Udarata Menike) was involved in the Watawala landslip incident.
These locomotives were originally imported for use on flat terrain, but they are very successful in upcountry line. Its flexicoil bogies and dynamic brakes allow it to perform well in the upcountry. Therefore, the M6 fleet is frequently used in upcountry line. M6 locomotives were used for upcountry express trains Udarata Menike and Podi Menike until 2012 and was succeeded by S12 & S14. M6 locomotives are currently used for upcountry Night Mail trains and Upcountry Commuter Trains.
M6 locomotives are painted either in standard livery or the class' unique ICE (InterCity Express) livery. The standard livery features horizontal green, brown and yellow strips. The ICE livery is brown and orange, a livery that is only painted on locomotives 785, 788, 797. No. 792 used to be in ICE livery in the 1990s, but has since been repainted in standard livery.
Loco numbers 793 and 798 were destroyed by terrorist attacks (793 was destroyed by a bomb blast between Puliyankulam-Vavniya on March 25, 1986; 798 was destroyed by a bomb blast at Thambalagamuwa on December 5, 1996). Loco number 786 was involved in the Yangalmodara level crossing accident.