SYX-RRL TYPE 4A traffic counter recorder: an electro-mechanical counter with a rubber pneumatic tube detector connected to a sensitive diaphragm air switch which is closed for a short period of time by pulses of air pressure and an electromagnet is energised. In turn each pulse displaces an armature whose motion is registered by a 5 digit tumbler display (“Elmeg” counter unit) in half unit intervals per pulse. The counter is powered by two 6 volt dry batteries. The counter is powered by two 6 volt dry batteries.
This counter was purchased (c.1963) by the City Engineer’s Department of Edinburgh Corporation and was used to count traffic at a number of locations in the city and possibly elsewhere in Lothian Region. This type of counter was not fitted with a clock so the readings on the display had to be manually timed to make sense of the recorded value. They were, therefore, only used for long-term and ad hoc counts where hour-by-hour data were not required.