The NBR K class is a class of 4-4-0 steam locomotive of the North British Railway. The first batch (later LNER Class D26) was designed by Matthew Holmes in 1902 and had 6-foot-6-inch (1.981 m) driving wheels for express passenger work. Three more batches (later LNER Classes D32, D33, and D34) were designed by William P. Reid with 6-foot-0-inch (1.829 m) driving wheels for mixed traffic work. This included perishable goods, such as fish from Mallaig and Aberdeen. They had inside cylinders and Stephenson valve gear. The D34 locomotives, commonly known as Glen Class, were built with superheaters. The LNER later fitted superheaters to all D26, D32, and D33 engines as well. All engines of the K class are sometimes known as Glen Class, although the designation is strictly reserved to the fourth