The LNWR 4ft 6in Tank was a class of 220 passenger 2-4-2T locomotives manufactured by the London and North Western Railway in their Crewe Works between 1879 and 1898.

From 1909 many locomotives of the class were fitted for Push-pull working, giving the nickname of "Motor Tanks".

Six locomotives were sold to the Dublin, Wicklow and Wexford Railway in 1902 for £1500 each, and re-gauged to 5 ft 3 in (1,600 mm).

Five were sold to the British Government in 1916, regauged back to 4 ft 8+1⁄2 in (1,435 mm) gauge;[2] two went to the Inland Waterways and Docks where they lasted until scrapped in 1919.

Withdrawals started in 1905: 118 were scrapped in the years up to 1923 grouping, leaving 90 to be passed to the London, Midland and Scottish Railway.