LMS Class 7F 0-8-0

LMS 7F 0-8-0

49592 at Aintree, June 1948.

Type and origin Power type Steam Builder LMS Crewe Works Build date 1929–1932 Total produced 175

Specifications Configuration 0-8-0 UIC class D h2 Gauge 4 ft 8 1⁄2 in (1,435 mm) Driver dia. 4 ft 8 1⁄2 in (1,435 mm) Wheelbase Loco: 18 ft 3 in (5.56 m) Length 56 ft 1 in (17.09 m) Loco weight 60.75 long tons (61.72 t; 68.04 short tons) Tender weight 41.20 long tons (41.86 t; 46.14 short tons) Total weight 101.95 long tons (103.59 t; 114.18 short tons) Fuel type Coal Fuel capacity 4 long tons (4.1 t; 4.5 short tons) Water cap 3,500 imp gal (16,000 l; 4,200 US gal) Firebox:  • Firegrate area 23.5 sq ft (2.18 m2) Boiler LMS type G7¾S Boiler pressure 200 lbf/in2 (1.38 MPa) Heating surface:  • Tubes and flues 1,434 sq ft (133.2 m2) later 1,402 sq ft (130.3 m2)  • Firebox 150 sq ft (14 m2) Superheater: ​  • Heating area 353 sq ft (32.8 m2) to 338 sq ft (31.4 m2) Cylinders Two Cylinder size 19 1⁄2 in × 26 in (495 mm × 660 mm) Valve gear Walschaerts, piston valves

Performance figures Tractive effort 29,745 lbf (132.31 kN)

Career Power class 7F Numbers LMS: 9500–9674 BR: 49500–49674 Nicknames Baby Austins Austin Sevens Withdrawn 1949–1962 Disposition All scrapped

The London, Midland and Scottish Railway Fowler Class 7F was a class of 0-8-0 steam locomotives. They were a Midlandised version of the London and North Western Railway (LNWR) Class G2 and Class G2A 0-8-0s. They were also classified as Class G3 under the former LNWR system. The class were sometimes known as Baby Austins, or Austin 7s, after a motor car that was becoming popular at the time.

It featured a Belpaire firebox and increased boiler pressure over its predecessor but had the same power rating of 7F. Unfortunately the design had been done at the old Midlands Railway's Derby Works and the drawing office staff insisted on using Midland practice. Among other things this meant that the axle bearings were too small for the loads they had to carry. E.S Cox, writing in a series of articles in Trains Illustrated c. 1957, suggests that they had a sufficiently modern and effective front end that, for steady slogging, some drivers preferred them to an LMS Stanier Class 8F. However, this also meant that, with bearings comparable to an LMS Fowler Class 4F and already inadequate for the lower powered engine, the bearings broke up rapidly.

Numbers 9672–74 were fitted with ACFI feedwater heaters when built but these were removed during the Second World War. After the war, five were briefly converted to oil burning.

They all survived to pass into British Railways ownership but 122 had been withdrawn by the end of 1951; fifty were withdrawn without receiving their BR number. They had a fairly short life and were all withdrawn between 1949 and 1962, some time before the G2s which lasted until 1964.