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 7th 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.

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.

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.

45050 was last used on riding tests with fly-ash wagons between Derby and South Wigston on 22nd August 1967, and was finally withdrawn in November 1970 and about to be cut up at the nearby scrap metal yard of Albert Looms at Spondon near Derby. However, Raymond Smith, a Testing and Performance Section Engineer and Brian Radford, a Senior Technical Officer from the C.M.E.’s Director of Design staff both thought that it deserved to be preserved as an historic vehicle. The latter wrote a letter asking that it be made available for future display in a proposed museum then being set up by Derby Museums. The request was passed to the then Chief Mechanical & Electrical Engineer. T.C.B. Miller who agreed to the proposal, following positive support from R.G. Jarvis, Mechanical Engineer Design (Derby) and members of the Testing & Performance Section.

After storage in the Derby the vehicle moved to the Midland Railway site at Butterley in September 1975 where it was re-painted in its original LMS maroon livery by S. Huson and members of the Project Group’s Carriage & Wagon Department, who also began some restoration work.

By 2002, being very conscious of the major historical importance of the vehicle and its relevance to the P.R.C.L.T’s ‘Acquisition & Collecting Policy’, an approach was made to the Midland Railway Trust for their formal agreement to 45050 being removed from their list of vehicles, since at that time it was nominally listed as being leased to them by Derby City Museums. After discussions, this was eventually achieved and the vehicle was moved into the P.R.C.L.T.’s West Shed on 15th January 2005, where it has since been on static display in its current state. March 2008 saw the award of a Heritage lottery Fund grant be awarded for 45050's restoration to its 1930's condition.