The Locomotives

The Locomotives

Image courtsey of Plateway Press


The Metropolitan Water Board put out to tender many of items required for the railway’s construction and operation including rails, wagons, and most significantly the locomotives. Despite outsourcing the building of many key components, the MWB was keen to design all aspects of the railway to ensure it met their detailed requirements. This included the locomotives which were designed in house and the tender to construct them awarded to Kerr Stuart & Co Ltd in 1913.    

The above drawing shows the MWB’s concept for the locomotives which differs slightly from the as built locos. The design demonstrates how the MWB was not content with off the shelf locomotives. Shortly after this drawing was produced, Kerr Stuart & Co Ltd responded with a modified proposed locomotive using some of Kerr Stuart's already in production parts including many components of the motion. Content with the designs, the MWB placed the order on the 29th of May 1914 at a cost of £678. This sum would increase, finally costing £729 each.


The locomotive’s works numbers were 2366, 2367 & 2368 and were named Hampton, Kempton & Sunbury accordingly.  Between the 15th September 1914 and the 2nd March 1915, some 87 separate drawings were produced for these engines.


The locomotives had outside cylinders and used Walschaerts valve gear which had the benefit of having exceptional large wearing surfaces. The coupled wheels had steel centres with rolled steel tyres. The trailing wheels were millers chilled with side motion controlled by spiral springs to eliminate hunting in use. A large dome was bolted to a seating on top of the boiler barrel which provided easy access to the regulator for repairs. The large dome and high regulator also helped to reduce priming on the very steep and rapid changing gradients on the railway. A mud drum was fitted beneath the boiler to collect the sediment aiding the boiler wash-out process. Water was fed into the boiler through an axle driven pump when in motion and an injector for when stationary. Cylinder lubrication was fed from two displacement lubricators mounted on the sides of the smoke box. These lubricators were later replaced by a mechanical lubricator on the right hand side of the locomotive. The engines only featured a handbrake and not any continuous braking system as they only ever hauled coal wagons. 

Driving wheel diameter                                                   24'' 

Fixed wheelbase                                                            36'' 

Cylinders                                                    8.5'' x 12'' stroke

Length over buffers                                                   15' - 3''

Height                                                                         8' - 3''

Working pressure                                              150 lbs inch

Boiler barrel                                              0.375'' steel plate

Grate area                                                                3.9 sq ft

Heating surface firebox                                             22 sq ft

Water tanks                                             170 gallon capacity

Weight empty                                                    9 tons 6 cwt

Brakes                                  Hand, on coupled wheels only

Fire door                                                             Sliding type

Trailing wheel diameter                                                  16.5''

Total Wheelbase                                                                84''

Driving axles                              3.25'' Dia journels 5.5'' Long

Width of footplate                                                                 6'

Safety Valves                                              1.25'' ramsbottom

Tractive effort                                                           4,480 lbs

Boiler tubes                                                49 tubes 0.75'' dia

Firebox                                                      Copper, 0.5'' thick 

Heating surface tubes                                            127.5 sq ft

Injector                    No. 4 automatic self starting simple type

Weight working                                                10 tons 15 cwt

Sanding                        4 boxes, all controlled from footplate

Image courtsey of London Museum of Water and Steam