Caledonian class 417

One of the Caledonian Railway classes of 2-4-0 goods locomotives with large driving wheels of 6 ft 2 in or 1.880 mm was the class 417. Designed by Benjamin Conner and introduced in 1866, it was a development of the class 288. Like their predecessors, the driving axles were mounted in inside frames, while the leading axle was mounted in the full-length outside frames. They too had inclined outside cylinders, but could be distinguished by the raised-top firebox. 

By 1870, 37 had been built by Neilson & Co. which received the numbers 417 to 436, 474 to 485 and 334 to 338. Starting with 474, the first driving axle had been moved three inches to the front. The tenders carried four tons of coal and either 1,580, 1,600, 1,700 or 1,770 gallons of water. The water capacity of all tenders was later changed to 1,800 gallons. 

Although most locomotives were rebuilt in the 1880s, the major rebuild by Dugald Drummond was done to only 25 locomotives between 1883 and 1886. There they received a larger flush-topped boiler with a higher pressure, Ramsbottom safety valves, a new injector and a Westinghouse air brake. In this configuration, they were classed as passenger locomotives. The heavier boiler led to many cracked frames which had to be fixed. In the late 1890s they were replaced by 4-4-0 locomotives and now used for secondary passenger and excursion trains and as pilots. They were withdrawn between 1898 and 1920.