Metropolitan Railway A Class

Metropolitan Railway A Class and
B Class

Metropolitan A Class No. 27

Type and origin Power type Steam Builder Beyer, Peacock and Company Build date 1864-1870 (A Class) 1879-1885 (B Class)

Specifications Configuration 4-4-0T Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft (914 mm) Driver dia. 5.75 ft (1,753 mm) Wheelbase 20.75 ft (6 m) Axle load 15.475 long tons (15.723 t; 17.332 short tons) Loco weight 42.1–45.2 long tons (42.8–45.9 t; 47.2–50.6 short tons) Fuel type Coke, Coal Water cap 1,000 imp gal (4,500 L; 1,200 US gal) (A Class) 1,140 imp gal (5,200 L; 1,370 US gal) (B Class) Boiler pressure 120–130 psi (8.3–9.0 bar; 830–900 kPa) (new) 150 psi (10 bar; 1,000 kPa) (modified) Heating surface:  • Tubes 912.6 sq ft (85 m2)  • Firebox 101.2 sq ft (9 m2) Cylinders 2 Cylinder size 17 in (432 mm)

Career Operators Metropolitan Railway District Railway London & North Western Railway Midland Railway Rheinish Railway (Germany) Number in class 148 (total) 40 (Metropolitan A Class) 26 (Metropolitan B Class) Retired 1935 Disposition One preserved, remainder scrapped

The Metropolitan Railway A Class and B Class were 4-4-0T condensing steam locomotives built for the Metropolitan Railway by Beyer Peacock, first used in 1864. A total of 40 A Class and 26 of the slightly different B Class were delivered by 1885. Used underground, the locomotives condensed their steam, and coke or smokeless coal was burnt to reduce the smoke.

Most locomotives were withdrawn after electrification in the early 20th century, forty having been sold by 1907. By 1936 only one remained, and this is now preserved at the London Transport Museum.

When the Metropolitan Railway (Met) opened in 1863 the Great Western Railway (GWR) provided the services with their Metropolitan Class locomotives. However, the GWR withdrew their services in August 1863, and the Met bought their own locomotives, which needed to condense as the line from Paddingdon to Farringdon was underground. A tender was received from Beyer Peacock of Manchester for building eighteen locomotives at £2,600 each that would be available in six months. The design of the locomotives is frequently attributed to the Metropolitan Engineer John Fowler, but the design was a development of a locomotive Beyers had built for the Spanish Tudela & Bilbao Railway, Fowler only specifying the driving wheel diameter, axle weight and the ability to navigate sharp curves.

The 4-4-0 tank locomotives delivered in 1864 had 16 in × 20 in (406 mm × 508 mm) cylinders, 5 feet 0 ¹⁄₂ inch (1.537 m) diameter driving wheels and weighed 42 ton 3 cwt in working order. The boiler pressure was 120 psi (830 kPa), the front wheels were on a Bissel truck and fitted with 40 cubic feet (1.1 m³) bunker. As they were intended for an underground railway, the locomotives did not have cabs, just a simple spectacle plate. To reduce smoke underground, at first coke was burnt, changed in 1869 to smokeless Welsh coal.