Banner
Navigation

Navigation

loco-info.com
The reference for locomotives and railcars

Great Western Railway class 7800 “Manor”

Great Britain 1938 30 produced
No. 7812 “Erlestoke Manor” in March 2014 at the Severn Valley Railway Spring Gala Peter Broster

The Manor class was designed in the late thirties when the GWR found out that the axle load of the mixed-traffic Grange class was too high for many lines. Therefore Charles Collett had the lighter Swindon No. 14 boiler designed, combined with a cylinder diameter that had been decreased by half an inch compared to the Grange. As with the Grange, the driving wheels, many motion components and the tenders were taken from old class 4300 Moguls. In the result the axle load had been reduced by more than a ton. After the first batch from 1938 and 1939, British Railways built another batch of ten in 1950. They were numbered 7800 to 7829 and named after Manors in the GWR area.

They could be used on many secondary lines in Wales and Devon. One task was to haul the Cambrian Coast Express on the last stretches where the Castle or King class were too heavy. Furthermore, they could operate into Cornwall since they were light enough for the Royal Albert Bridge. On the other side, they had a poorer steaming capacity than expected, what could not only be traced back to the small grate. After this had been investigated in 1951, their blast pipe area was reduced and air flow in the grate was improved. After this, they delivered nearly the same power as the Grange.

The first one was withdrawn in 1963 and all others followed in 1964 and 1965. Remarkably, nine of the class of 30 locomotives were preserved. While these include four of the original batch of locomotives built by the GWR, five out of ten of the BR batch still exist. All of these had run in preservation at some point. Four of these are still in working order today.

Technical data

General

Built
1938-1939, 1950
Manufacturers
Swindon
Wheel arrangement
4-6-0 (Ten-wheeler)
Gauge
1,435 mm (Standard gauge)

Dimensions and weights

Length
18.83 m
Wheelbase
8.26 m
Total wheelbase
15.89 m
Service mass
70 t
Adhesion mass
51.2 t
Total mass
110.6 t
Rigid wheelbase
4.50 m
Axle load
17.5 t
Water capacity
15,910 l
Fuel capacity
7.1 t (coal)

Boiler

Grate area
2.053 m²
Firebox surface
13.006 m²
Tube heating surface
119.427 m²
Evaporative heating surface
132.433 m²
Superheater surface
17.652 m²
Total heating surface
150.1 m²

Power plant

Driver diameter
1,727 mm
Boiler pressure
15.5 bar
Expansion type
simple expansion
Cylinders
two, 457 x 762 mm

Power

Power source
steam
Estimated power
969 kW (1,317 PS)
Starting effort
121.6 kN

Calculated values

Factor of adhesion
1 : 4.13
Optimal speed
48 km/h
Power-to-weight ratio
13.8 kW/t
Heating Surface Equivalent
232.8 m²
Cylinder volume/HSE
1 : 1,074.89
Adhesive weight/Total
1 : 1.37
Tractive force/Heating surface
1 : 16.92
Grate area/Heating surface
1 : 73.11
Firebox/Tube surface
1 : 9.18
Total/Superheater
1 : 7.50

Topics

  • steam locomotive
  • passenger
  • freight
  • Charles Benjamin Collett
CompareComment
Last changed: 02/2026

Watch on YouTube

Auf Deutsch umschalten

Settings

Your settings are retained for this browser session only.

Consent to cookies

We use cookies to save your display settings. If you decline, the settings are retained only for the current browser session.