"The huge locomotives of today didn't grow up by rule of thumb. The dynamometer car is largely responsible for the scientific progress of the latest 'locos'" L/S of a stationary train. Two men stand beside the train. C/U from low angle of carriage of the train which has the words "Dynamometer Car" painted on the side. C/U of man looking at the wheels of the train. Low angle of three men, one straddles between two carriages, the other two sit on the roof of one of the carriages. A device is attached to the carriage on the right, joining it to the carriage on the left. M/S of the front of the train. Men climb up into the engine driver's cabin. "In telephone touch with the driver - or Engineer on the footplate - within this special North Eastern car is a mass of valuable recording machines - each telling its own tale in graph or other form..."

C/U of two men at work in the special carriage. C/U of a piece of equipment. View from the moving train of the surrounding countryside. Another train passes by. C/U of instrument dials. C/U of man sitting in the special carriage with piece of equipment in front of him. "From here the Engineers can 'phone their footplate confreres and regulate speed, steam pressure or make other adjustments." M/S of the men at work. C/U of measuring machinery. "In this very private car delicate machines record the exact power exerted every second - also speed, distance, wind-pressure and a thousand and one other items." C/U of measuring tools. Shot of the train tracks from the moving locomotive. C/Us of various measuring machines. "The result - just a long roll of paper - but full of vital information for the Engineering Experts." C/U of a section of paper with "To York" and "To Darlington" printed on it. There are various scribbles made by the engineers. Information about what the various squiggly lines represent appears as if by magic on the page. C/U of this information.

Was an item in Pathe Pictorial issue number 498.

Note: flash-frame intertitles.