The Class K design was not just small, it was diminutive, and as class Y8 these were the smallest steam locomotives used by the LNER. They were fitted with steam and hand brakes only, never having vacuum brakes, and were unusual in having no bunker behind the cab for the coal, but rather having the small amount of coal required stored in a bin at the back of the footplate. The Y8s were built with 'marine' type boilers, i.e. with a cylindrical flue into which the grate fitted. Between 1902 and 1904, they were all re-boilered with more traditional boilers similar to those fitted to the NER Class H locomotives. Originally all of the Y8s were fitted with a single whistle of the bell-shaped type. 560, 561, and 563 acquired the organ type during LNER ownership. 559 also had one of these whistles fitted, but after 1940. In 1942 LNER No.8091 acquired the chime whistle from the Gresley A4 4469 Sir Ralph Wedgewood when it was damaged during an air raid on York in 1942. By 1946, the original organ-pipe whistle had been restored.
Operation and preservation
The NER built the K class specifically to shunt the docks at Hull, and it was here that they performed for most of their lives. During World War I No.559 was used both at Woolwich Arsenal and by the Royal Engineers near the mouth of the Humber Estuary. In 1940-41 559 spent a second period on the Spurn Head Railway. No 8091 became Departmental Locomotive No. 55, and acquired a 50A shed plate, being the last of the class when finally withdrawn in June 1954. All five K class locos survived into LNER ownership. However, the Depression-era reduction in dock traffic and the increased use of Sentinel shunters led to the scrapping of three Y8s in 1936/7. Numbers 559 and 560 survived to the 1946 renumbering, and were renumbered as 8090 and 8091 respectively. Both survived into British Railways ownership, but neither survived long enough to acquire an updated '60000' number plate. 8090 was withdrawn in November 1948. None of the original five survived into preservation. There have been rumours that a replica of this class of engine may be built for use at Beamish Museum where its small size and marine type boiler are seen as perfect for the museum's short demonstration line.