The interaction of a high speed train pantographs with overhead lines is an important area within the rail industry. One particular trial required footage of the wave created by the contact force of the pantograph. Unusually regards high speed filming, the trial had to be done at night. Having previously worked on a similar day time trial, Slowmo Ltd was called on to provide the images.
The Photron SA-X2 mono high speed camera was the obvious choice for this application because of its industry leading light sensitivity. In order to illuminate the wires and pantograph, one of Slowmo’s powerful LED floodlights was used. As the floodlight is only rated at 200W (for 2KW tungsten equivalent) a small briefcase type generator was used for power. The camera was set low on a tripod, angled upwards towards the wires and a field of view of around 6m was set using a 50mm F1.4 lens.
With this night time set-up, amazingly a high speed train was able to be filmed at 2000 fps. Furthermore, the clarity within the image allowed one to easily assess the movement of the overhead wires as the pantograph passed underneath. Images over 3 consecutive nights were then recorded.