Local Thorn Alpha 2000s

The Alpha 2000 was the lantern of choice to provide illumination for the A50 Southern Derbyshire Bypass (and associated junctions) when it was constructed in the mid-late 1990s; indeed, my own example was removed from this road's junction with the A38 at Burnaston as part of a scheme to replace a number of Philips MA 60 180 W SOX lanterns on the A38 with Urbis ZX3 lanterns in 2005. For some reason, a few Alpha 2000s were included within this replacement work, despite the new lanterns utilising the same lamp type and wattage as the Thorn lanterns had. Despite this, and a further relighting scheme on the A38 in 2015 using Philips Iridium2 lanterns, numerous examples of the Alpha 2000 can be seen on the A50, and surrounding roads, to this day.

This Alpha 2000 is to be found on the approach to the Thulston Roundabout, on the south-eastern side of Derby.

 

Unusually, this example is fitted with its own photocell; most of the examples on the A50 itself are group-switched.

 


12 m columns supporting 250 W SON-T Alpha 2000s are installed on the roundabouts above the A50; these examples are pictured on that road's interchange with the A38, near the Toyota car factory.

 

This close-up reveals that the lamp (and therefore, the lampholder too) is completely out of the correct focusing position within the optic. The lantern fitted to the column behind this example in the above picture was in similar condition.

 

The main carriageway is lit with 150 W examples.

 

The majority of columns are mounted in the central reservation on twin-arm brackets, although some single-arm examples exist at the points where there are emergency lay-bys, as seen above.

 

As mentioned above, the majority of the lanterns employed on these scheme are group-controlled; therefore, individual photocells are not fitted.

 

An oddity with the Alpha 2000's design is that the front panel on the top section of the canopy appears to be removable, and indeed, it is; however, the rest of the canopy must be hinged open first, and the panel unscrewed from inside. Perhaps an earlier version of the design allowed the panel to be opened from the outside, in order to access the lamp area without opening the whole canopy.

 

At Hilton, where the A50 meets the A516 and A5132, Alpha 2000s are installed beneath the bridge supporting the dual carriageway. Owing to the limited height clearance here, the columns are 6 m in height, although the lanterns are still equipped with 150 W SON lamps. One of the two examples is pictured below.

 

Heavy corrosion is present to the aluminium bodywork of these lanterns (something not witnessed with any of the other Alpha 2000s), and because of the reduced mounting height, the flat glass cover has been smashed by vandals at some point in the past.

 

On the night of Thursday, 28th April 2017, some of the Alpha 2000s on the A6 'Derby Spur' link road between the A50 and the A6 itself were replaced with OrangeTEK 'AriaLED' lanterns.

 

Owing to the lighting being group-controlled, neither the Alpha 2000s, nor the AriaLEDs, are fitted with photocells.

 

I assume that the remaining Alpha 2000s on this road and junction are set to be replaced themselves at some point.

 

The mixture of golden light emitted by the Alpha 2000s and the much whiter light emitted by the AriaLEDs must make for an interesting sight after nightfall.

 

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