Thorn Alpha 5 lantern. Developed from the 1960's Atlas Amberline lantern, the Thorn Alpha-5 is a remote-geared lantern designed for use with either SLI/H  linear sodium lamps or singled ended sodium lamps (135w/150w SOX). Intended for use on main roads, the Alpha 5 was once a popular choice with many local authorities around the UK and examples were once plentiful. However, despite being available from Thorn until the 1980's, the Alpha-5 is now in rapid decline and it's getting harder to find survivors in reasonable condition. The 135w/150w SOX example in the collection came from Wolverhampton in the West Midlands.

The basic shape of the Alpha 5 remained more or less unchanged until production ceased in the 1980's; however, it was available with either a shallow bowl or deep bowl and this is the only noticeable difference from street level. Although longer in length, the Alpha 5 has a striking family resemblance in its design to the Thorn Beta 8 and Thorn Alpha 9 lanterns, and indeed looks like a stretched Beta-8. Unlike the smaller Beta 8 and Alpha 9, it does have a dedicated vee reflector plate incorporated above the lamp. Access to the lantern is gained by releasing the two large spring-clips situated at the side of the lantern's canopy, which allows the long plastic bowl to hinge downwards on its side mounted hinges.

The lantern in the collection is in very good condition, but does require a better bowl as there is a burn mark in the bottom of the bowl from where the lamp must have once rested - possibly due to the lampholder coming adrift in the past? Aside of that, the Alpha5 doesn't need much doing to restore it, other than a good clean up and the replacement of the lamp support hoop.

Side view of the deep-bowled Alpha 5 lantern held in the collection. Fortunately this example has not been drilled for photocell fitment. The pencil gives an idea of the lantern's overall size.

The lantern with its bowl open showing the lamp and vee reflector plate above it. A piece of wire supports the lamp, as the lamp support-hoop is missing and will need replacing.

 An underview of the Alpha 5's bowl showing the hinges and two wire fastening clips that hold the bowl in position.

An in-service deep-bowled Alpha-5 seen in Wolverhampton in 2005. Like most remaining Alpha 5's this one burns a re-rated 135w SOX sodium lamp, but was originally intended for use with a 150w SOX sodium lamp. This particular installation dates from about 1973-4 and replaced a mixture of old mercury and sodium lanterns mounted on redundant trolleybus traction poles.

As a comparison, here's a shallow-bowled Alpha-5. However, the shallow bowl is synonymous with linear lamped Alpha-5’s, so is thought to be unusual on the SOX version of the Alpha-5. An explanation might be that the shallow bowl was a retro fitted in-service replacement?  Note how low the lamp lies in the bowl, and also the two-part photocell mounted on the column top.

Another shallow-bowled Alpha 5, but this one is for SLI/H lamps. Situated on an industrial estate in Wolverhampton, it has sadly been vandalised with air rifle pellets.

Here are some other 'Alpha' family lanterns to look at as comparisons:

Alpha 9 Deep-bowl lantern,
Alpha-9 shallow bowled 'geared' lantern
Beta 8