Working Life


45050 L&Y Dynamometer Car

This dynamometer car was built by Lancashire & Yorkshire Railway in 1912 to the requirements of George Hughes, C.B.E., the company’s Chief Mechanical Engineer, and ran its first trials on 7 th February 1913 testing the performance of the first of Hughes 4-6-0 four cylinder express passenger locomotives No.1506.

The dynamometer car is attached behind the locomotive and is used to measure its performance by means of a drawbar attached to a nest of horizontally placed springs beneath the floor which deflect under load. An arm connected to the springs comes up through the floor and transmits the deflection up to the recording table, allowing it to be used to calculate the horsepower generated by means of a mechanical integrator mounted on the table. The output is then automatically recorded by means of one of several pens making traces on a moving roll of paper drawn under them at a known rate.

An independent road wheel with a diameter of 33.613 inches is located between the bogie wheels near to the observation or ‘balloon’ end of the car. This can be lowered by a screw onto the track and used to drive, by means of bevel gears and shafting, all of the elements of the instrument table which depend on the running speed and recording distance travelled.

Other information is also recorded such as water and coal consumption which are marked on the dynamometer car roll during the tests. By means of visual observations by engineers seated high up in the ‘balloon’ end of the car, which is always next to the tender, each shovel-full of coal delivered into the firebox can be noted, whilst the consumption of water is measured by a pre-calibrated ‘U’ tube gauge. With no telephone communication with the footplate staff, events are recorded by using a bell push and a system of bell codes and marked as ‘events’ on the moving roll of paper.

The recording table of dynamometer car No. 293 as built
showing the circular integrator on the right and the
clockwork timing clock on the left. Beyond is the moving
paper roll, fed from a reel on the left and taken up on the lower right,
upon which the various ink pens make traces showing
deflection of the drawbar springs, time and distance
travelled and other events such as water and coal
consumption are marked. (Lancashire & Yorkshire Railway Official)

Taken over by the L.M.S. in 1923, this historic vehicle was used to test such locomotives as Fowler’s ‘Royal Scot’ class 4-6-0’s, Stanier’s ‘Princess Royal’ and ‘Princess Coronation’ class 4-6-2’s, and took part in the 1948 Locomotive Exchange Trials to evaluate various locomotive types used by the four main companies, resulting in the design and building of the British Railways Standard range of steam locomotives, which it was also subsequently used to test.

As yet without smokebox door number plate,
Stanier 4-6-2No. 6200 ‘The Princess Royal’, with
dynamometer Car No.1 behind the tender, at speed on
the ‘Special Limit’ timings testrun of 15 th August 1933
between London Euston and Crewe. (J.B. Radford Collection)

In 1948 it was also used to test the first main line diesel electric locomotives used on Britain’s railways, Nos 10000 and 10001, and also later generations of diesel motive power. It was withdrawn in 1967 and fortunately saved for preservation.

Built at the Newton Heath Carriage Works of the Lancashire & Yorkshire Railway in 1911 the vehicle moved to the company’s nearby Horwich Locomotive Works for final fitting out. It was painted in the company’s livery and numbered 293, and ran its first trials on 7 th February, 1913 testing the performance of the Hughes four cylinder 4-6-0 express passenger locomotive No.1506.

With the arrival in 1932 of William Stanier, the car was used to test his new locomotives, including the large and powerful 4-6-2 ‘Pacific’ types built from 1933 onwards. The dynamometer car, now renumbered 45050 and designated ‘L.M.S. Dynamometer Car No. 1,’ was used to record the performance of Stanier 4-6-2 No. 6200 ‘The Princess Royal’ on the ‘Special Limit’ timings test run on 15 th August, 1933, and also the special run of No. 6201 ‘Princess Elizabeth’ when she ran non-stop between London and Glasgow, a distance of 401 miles on 16 th November, 1936, also returning non-stop the following day. The findings enabled further developments to take place and the ‘Princess Coronation’ class of streamlined 4-6-2’s to be developed – the most powerful type of express passenger locomotives ever to run in the British Isles.

It was subsequently used to extensively test the new types of B.R. Standard steam locomotives built as a result of these trials, as shown on the photographs taken during trials with 4-6-2 No. 70000, yet to be named ‘Britannia’. And when the new generation of diesel electric locomotives came along from 1960 onwards, the dynamometer car continued in use carrying out performance tests on those.

Working Life - Restoration - Preservation