Steam Locomotives of a More Leisurely Era – 1922 – Gresley ‘Pacifics’ Great Northern Railway

Steam Locomotives of a More Leisurely Era

1922 – Gresley ‘Pacifics’

Great Northern Railway

No.1473 as first built

The final express design for the Great Northern, introduced by Mr. (later Sir) Nigel Gresley in 1922 just before the grouping.  Two engines were built initially, Nos.1470 and 1471.  They were a revolution in the size of power for express working on the GNR, which had hitherto been almost exclusively in the hands of the Ivatt ‘Atlantics’.  They were the only engines (apart from ‘Henry Oakley’) on that line ever to bear a name, No. 1470 being appropriately ‘Great Northern’, and 1471 ‘Sir Frederick Banbury’.  They may in some ways be regarded as a natural enlarged cross-development between the ‘Atlantics’, with their wide fireboxes, and the 3-cylinder K3 2-6-0s detailed in the previous post In this category.

Ten further engines quickly followed in 1923, Nos. 4472-81 (at first temporarily numbered 1472-81), whilst in 1924-5 there appeared Nos. 2543-82.

In 1925 No. 4474 underwent trials on the Great Western main line, being matched against the GWR engine No. 4079 ‘Pendennis Castle’, as a result of which No. 4480 was in 1927 rebuilt with a 220 lb. boiler, and four others were likewise treated a few months later.  Following the success of this conversion, further new engines were built with the higher pressure between 1928 and 1935, Nos. 2743-52, 2595-9, 2795-7 and 2500-8.  From 1925 onwards all the class were named, mostly after famous racehorses, but No. 4472, one of the best known of the whole lot had already become ‘Flying Scotsman’ after the train of that name, which it frequently worked.

All eventually received the higher boiler pressure, and in 1945 Thompson rebuilt the initial engine No. 4470, when it was considerably modified, and as such became the prototype of a new class of his own, comprising in all fifty engines.  This locomotive received the number 113 under the 1946 renumbering scheme, whilst the remainder became 35-112, and later ran as BR 60035-60112, the Thompson rebuild and subsequent additions being 60113-62.

As Built – Driving wheels – 6’ 8”,  Cylinders (3) – 20”x 26”,  Pressure 180 lb.,  Tractive effort – 29835 lb.,  Weight – ___ ,  GNR & LNER classification – A1 (later A10),  BR classification – N/A

As Rebuilt – Driving wheels – 6’ 8”,  Cylinders (3) – 19”x 26”,  Pressure 220 lb.,  Tractive effort – 32910 lb.,  Weight – 96 tons 5 cwt ,  GNR & LNER classification – A3,  BR classification – 7P6F

No. 4470, modified by Thompson – Driving wheels – 6’ 8”,  Cylinders (3) – 19”x 26”,  Pressure 250 lb.,  Tractive effort – 37400 lb.,  Weight – 101 tons,  GNR & LNER classification – A1,  BR classification – 7P6F