The North Eastern Railway class O was designed by Wilson Worsdell to supplant the 2-4-2T suburban tanks of his brother Thomas. Between 1894 and 1901, 110 were completed at Darlington. They now had the 0-4-4T wheel arrangement and a higher tractive effort than their predecessors with a symmetric wheel arrangement. Although they had no leading axle, they were good for 60 mph between stations with a longer distance.

In 1923, they became LNER class G5. In the following decades they got no major rebuilds, but all survived until the founding of British Railways in 1948. The first one was withdrawn in 1949, but larger numbers only followed in 1955. By 1958, all were gone and scrapped. At Shildon, the Class G5 Locomotive Company Ltd. is now building a replica that will be numbered 1759.