Model Spot – Accurascale KUA Nuclear Flasks
Simon Bendall .reports on the latest KUA Nuclear Flask carriers from Accurascale.
Newly released by Accurascale is a model of the Ministry of Defence’s KUA nuclear flask wagons as currently used on workings to Devonport and, occasionally, Georgemas Junction. Simon Bendall takes a look at the sizeable OO gauge model and the history of the wagons.
The need for the Ministry of Defence to have its own nuclear flask wagons dates back to the 1960s and the introduction of the first nuclear-powered submarines by the Royal Navy. The irradiated fuel produced by their reactors would need to be transported from the dockyards at Chatham, Devonport and Rosyth to Sellafield for reprocessing.
To this end, a single but substantial flask wagon was delivered by Head Wrightson in 1963, numbered in the private owner wagon series as MODA95780. Running on four six-axle bogies, it measured 89ft in length and was dubbed the ‘Hot Core’ wagon. When loaded, the specialist flask would be suspended between the wagon’s substantial girder sides and be accompanied by two converted Mk 1 escort coaches, carrying armed police and dockyard workers, as the fuel was far more ‘sensitive’‘ than what was
produced by nuclear power stations. This wagon performed its occasional task for some 30 years, by the end of which it carried the TOPS code of KMX. It was then held in reserve into the early 2000s.
The main drawback of the ‘Hot Core’ wagon was its restricted speed, this being 35mph whether loaded or empty. Therefore, two replacements were introduced from 1994, built by Bombardier Prorail, numbered MODA95782/83 and coded KXA. These were still sizeable wagons at 74ft long and they rode on four two-axle bogies with a maximum speed of 60mph. The look was much more modern and followed the practice set by some European designs in having a two-part sliding cover over the flask well. Their service life was short, though, and both had disappeared from the scene by around 2010.
Current wagons
The next pair of MOD flasks to be constructed were MODA95770/71 in 1997, again by Bombardier, and these remain in use today. For a while the four wagons operated together at a time when decommissioning of older submarines was at a peak. These newcomers were initially given the international numbers of 33 70 9985 003/004 and coded KYA but they were soon renumbered, gaining the aforementioned private owner identities and the revised coding of KUA. They again had 16 wheels and a similar design style, but they were longer at 81ft.
It is these two KUAS that have been produced in model form by Accurascale. Up to the mid-2000s, they were hauled by EWS traction. During that time they worked as required from Rosyth and Devonport to Sellafield, although the famous Scottish shipyard would cease to use rail traffic around four years later. Escort coaches under EWS were a pair of modified inspection saloons, DM45020 and DB999509, both carrying maroon and gold after previously sporting Regional Railways colours.
Direct Rail Services took over the MOD nuclear contract from 2006 and has continued to work the trains to and from the Plymouth Dockyard ever since, with a variety of traction ranging from Class 20/3s to Class 66s. Actual loaded runs typically amount to one or two a year, but additional training or maintenance runs also occur from time to time. DRS also has its own escort coaches, the original pair being Mk 2a BSO 9419 and 9428 and, more recently, Mk 2e BSO 9506 and 9508.
The ongoing decommissioning of the Dounreay nuclear site near Thurso has also seen the KUA make occasional trips to the Far North Line in recent years to bring back some of the more hazardous material to Sellafield. These have typically run with the escort coaches as well, although this has been more about spreading the weight of the train over weak bridges than any security aspect.
Big and blue
Accurascale first announced its intention to produce the KUAS in OO gauge in November 2019, having reached agreement with Revolution Trains to share its research data put together for its own N gauge model, which was released to much acclaim last year. To make the project viable, both MODA95770 and MODA95771 have been produced and these are only available packaged together as a twin set. Priced £159.95, this pack can be ordered directly from Accurascale or purchased from selected retailers across the country.
The result is an immense pair of models that are right up there amongst the biggest wagons ever seen in ready-to-run form in 4mm scale, their nearest rival in size and presence being the Oxford Rail railgun. The main spine of the wagons is diecast metal, to give weight and rigidity, to which have been added the plastic flask cover, lots of small details and the complex bogie arrangement with articulated sub-beams. As statement models go, it is impressive.
Welcomely, Accurascale has passed on the opportunity to make the flask cover functional, preferring a nicely -rendered plastic moulding to a gimmicky sliding hood with obvious joints. This decision also enables more weight to be packed in underneath. The rest of the main superstructure features other details, including the superfluous train ferry lashing points, wire grabs on the ends of the cover and presentations of the runner rails for the latter.
"The result is an immense pair of models that are right up there amongst the biggest wagons ever seen in ready-to-run form in 4mm scale."
Pivot points
Each bogie assembly features three points of articulation, the two bogies themselves and the sub-beam, above which the bogies connect to the main frame. This is all well engineered with enough vertical give built in to cope with uneven track and joints. The detail included is also excellent. The air brake equipment shoehorned in between the beams and walkways are the highlight. The walkways themselves have some fine chequer-plate detail moulded onto them, and the surrounding handrails are wire and particularly rigid.
Other details include stiffly sprung plastic buffers and bogie-mounted NEM coupling pockets with bufferbeam air pipes in the accessory bag. Given their cargo, the KUAS are, of course, festooned with data panels and notices, which are all reproduced in miniature to a high standard to complete another striking release from Accurascale.