The class was built to test the merits of superheaters. They were fitted with a saturated boiler (692), Schmidt superheater (693) and Robinson superheater (694). Judged a success, 692 was fitted with a Robinson superheater in December 1916. Further examples were planned with the completion of the North Coast line, but the C19 class were ordered instead.[1]
In March 1915, 693 was named Sir William MacGregor and 694 Lady MacGregor after the Governor of Queensland and his wife. All were converted to CC19 class with fitting of 19 inch cylinders in the 1930s.[1]
References
^ abcTurner, Jim (1997). Australian Steam Locomotives 1896-1958. Kenthurst: Kangaroo Press. p. 64. ISBN086417778X.