The K-3 was a series of 70 Pacifics delivered between 1910 and 1913 to the Grand Trunk. They had been built by Baldwin, Montreal Locomotive Works and the GT's own workshops. There were several batches from K-3-a to K-3-g which differed mainly in the valve gear. They later got thermic syphons, what increased their firebox heating surface by around 50 square feet. The specs given below already include the thermic syphons. The K-3-g differed from the others by having more boiler tubes and a cylinder diameter that was one inch smaller. The class was retired between 1950 and 1961. No. 5588 "Spirit of Windsor" is the only one that has been preserved, it can be found on display at Windsor, Ontario.