High Quality Content by WIKIPEDIA articles! 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` 6" driving wheels for express passenger work. Three more batches (later LNER Classes D32/D33/D34) were designed by William P. Reid with 6` 0" 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. Later locomotives had superheaters.