The story
G&R Wrenn's first product line was trackwork for 00 gauge model railway equipment, producing a variety of points and crossings for both 2- and 3-rail formats.
Initially located at Lee Green in southeast London, the company moved in 1955 to new larger premises in Basildon in Essex, where it remained until its final dissolution in 1992. In October 1957 the family partnership was formed into a limited liability company, G&R Wrenn Ltd.
Slot-car racing
In 1960, the company branched out into electric car racing toys similar to Scalextric but whereas Scalextric adopted the popular 1/32 scale, Wrenn produced their "Formula 152 model racing system" to 1/52, and with a twin conductor rail on each side of the 'slot' the system was capable of running three cars at a time on each lane. The smaller scale meant that quite comprehensive circuits could be fitted on to an 8' x 4' baseboard, but generally, electrical conductivity was quite fragile, so many users adopted a practice of a second conductor track piece on the far side of the circuit.
Some accessories were marketed, such as track barriers, lap counters, pit buildings etc., but as the only proponents of the 1/52 scale, the system was never popular,
The original cars were a Ferrari and a Cooper and used an electromagnetic ratchet and pawl system and a contact breaker, rather than the more traditional wound electric motors. This first motor could be run on 16v AC or 12v DC current, with AC current providing slightly more power. Power was either 'on' or 'off' and cars would freewheel around corners, needing a totally different driving technique to variable speed motors. Cars could only run for a short time as they were rather prone to overheating, and performances varied wildly, according to contact and brush settings. Next Wrenn introduced a Vanwall and a Maserati into the vibrator-motored range of cars. Later developments moved on to more traditional DC motors with a variable speed control. Then all of the existing cars were available with this new motor and finally a BRM and Porsche were added to the rather limited range.
Wrenn set up a '152 Drivers club' complete with metal badge and a short lived newsletter.
Other products included battery-operated boats.
From Wikipedia’s article on G & R Wrenn, shared under CC BY-SA 4.0.3