153. Mansfield Road, Clowne Still attached to many of the Stewart & Lloyd 25 ft tubular steel columns installed along this main road are a small number of Atlas Alpha One 90 Watt SOX lanterns, likely to date from the mid-to-late 1960s. The differences between the Atlas and later Thorn Alpha 1s are explained below; suffice to say, although Thorn versions are themselves rare these days, Atlas examples are nowadays exceptionally thin on the ground.


Sadly, the lanterns are not in the best of conditions - although this lantern's Opticell (the acrylic casing surrounding the lamp) is clean, it has has to be secured using lengths of insulation tape. A Zodion SS55-style two-part photocell detector can be seen attached to the lantern's aluminium shoe.


I always like the combination of a Stewart & Lloyd column (ideally with a cranked bracket) and Alpha 1 lantern.


Although now running 90 Watt SOX lamps, these lanterns are old enough to have been fitted with 140 Watt SOI/H lamps (and possibly even the precursor, the fabulous SO/H lamp with replaceable arc tube) originally.


The Atlas version of the Alpha 1 differs from the Thorn version in that the Opticell in these is secured by a thumbscrew located in the underside of the shoe; this design was superseded with a sprung toggle for the Thorn version. Another change that Thorn made was for the placement of internal equipment to be altered, in order that they no longer had to be screwed to the shoe; thus, the two closely-spaced screws (near the Opticell end) were no longer required.


The Opticell on another Alpha 1 was in slightly worse condition.


This one clearly showed signs of water ingress, although it still appeared to be secured by means of the thumbscrew.


A Royce Thompson S400 (P42E) two-part photocell detector is seen here.


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