Rail Detector machine is used to register track defects - machine seen in operation.
"Usually, fault finders are an obnoxious class, but not this one...it concerns trains...and tracks." L/S of criss crossing train tracks. A train approaches the camera. C/U of the train track. Train passes over it.
"The Fault-finder, or Rail Detector, is a delicately balanced machine which, placed in a train, automatically resisters track level defects." C/U of a piece of complex machinery. How it works is explained in intertitle. C/U of the machine in situ. Camera tilts up to show operator standing at the window of the train pressing a bulb which registers any faults in the track. C/U of operator leaning out of the train window. He wears goggles.
C/U of the machine as paper record is printed out. We see one of the records in C/U - squiggly lines on a piece of paper show how train passed through Hatfield at 60 mph. M/S of the operator leaning out of train window as train moves at speed. "Later, the experts proceed to any point where a defect is indicated and true up the track." M/S of several men at work on the train tracks.
Was an item in Pathe Pictorial issue number 573.
Note: may be Hatfield in Hertfordshire.