The 3521 Class were forty tank locomotives designed by William Dean to haul passenger trains on the Great Western Railway. They were introduced as 0-4-2 T locomotives in 1887, but were quickly altered to become 0-4-4 T s to improve their running.

GWR no. 3521 had been built as a standard-gauge 0-4-2 T in 1887, and no. 3546 as a broad-gauge 0-4-2 ST in 1888. They had each gone through several stages of rebuilding, becoming standard-gauge 4-4-0 tender locomotives in 1899 and 1900 respectively.

Due to the unsteady running of the 0-4-2STs, the last of the order, 3660, was turned out in August 1889 as a 0-4-4T bogie side tank. The remainder of the cla...

GWR 3521 Class 4-4-0 No 3531 is seen at the head of a local down service to Stourbridge comprised of four-wheel coaching stock. The 3521 Class started life as a class of 40 tank locomotives designed to haul passenger trains on the Great Western Railway.

Swindon 3521 Class. The short and unhappy history of the 3521 class as rather hopeless 0-4-2 tanks is dealt with in the 4-4-0 article. They had P Class (Dean Goods) boilers – larger than any other 0-4-2s, a 7' 6" + 10' 6" wheelbase and a reluctance to stay on the rails. Rebuilding, updating and withdrawal: Swindon 3521 Class

The 3521 Class were forty tank locomotives designed by William Dean to haul passenger trains on the Great Western Railway. They were introduced as 0-4-2T locomotives in 1887, but were quickly altered to become 0-4-4Ts to improve their running.

Class 3521 (Locobase 3552) An odd arrangement for a tank engine. This class had a long wheelbase between the trailing driving axle and the trailing carrying axle.

GWR 4-4-0 '3521 class' No 3529 is seen arriving at Snow Hill ready to take forward a local stopping train to Hartlebury and Severn Valley. The 3521 class were originally designed in an 0-4-2T configuration for both Broad gauge and Standard gauge, with No 3529 being one of the twenty locomotives built for Standard gauge.

GWR 4-4-0 3521 Class No 3555 stands over the ash pits at Tyseley shed having just been coaled. The 3521 Class started life as a class of 40 tank locomotives designed to haul passenger trains on the Great Western Railway.

The 3521 class had perhaps the most convoluted modification history of any GWR class, and in their original form were arguably the worst locomotives ever built in any numbers in Great Britain! They were built as 0-4-2 tank engines and had a short 7'6" coupled wheelbase, and then a 10'6" gap to a trailing wheel which, according to every source I ...