Accurascale adds Mirrlees Class 37/9s and new 37/4 variants

Accurascale’s third Class 37 run is the one that goes past the obvious and into the gaps serious OO gauge modellers have been waiting to fill. The headline change is not just another repaint cycle, but two new variants that were not previously available off the shelf in this form: the first ready-to-run Class 37/9s with Mirrlees engines, and a new batch of Class 37/4s built with all-new tooling.

The 37/4 is the cleaner buyer’s story to decode because the differences are physical and practical. Accurascale said this production run was tooled specifically for the subclass, with an operating roof fan that is synced to the DCC sound file and also works on DC. The new body shells also carry separately applied bonnet-top doors and enhanced grilles. That puts the model squarely at the modellers chasing mid-1980s refurbished locomotives, not just anyone who wants a generic green or blue 37 on the shelf. It is the version for layouts that sit in the later BR and sector-era sweet spot, where detail changes and refurbishment matter as much as the livery.

The 37/9s are the sharper hook for prototype followers. Accurascale said the Mirrlees-powered Class 37/9s were an off-shoot of the ill-fated Class 38 project, with six locomotives built in total, four fitted with Mirrlees engines and two with Ruston prime movers. The first pair, 37901 and 37902, left Crewe at the end of October 1986. That makes the new OO gauge release especially useful for anyone modelling the short-lived experimental end of the class, where the story is as much engineering oddity as locomotives. It is also the first time Accurascale has tackled a ready-to-run Mirrlees 37/9 in this scale.

All of it sits inside a class that still makes commercial sense for repeat tooling. Accurascale describes the Class 37 as a 309-strong mixed-traffic English Electric Type 3, and that sheer spread of sub-classes is the reason a third run can still feel fresh. The type stretches from the original 37/0s through regeared 37/3s, electric train heating 37/4s, refurbished 37/7s and the rebuilt 37/9s, so every new tooling decision opens another slice of BR history.

Retail stock for the third-run 37/4s and 37/9s was arriving in May 2026, with Key Publishing’s exclusive 37702 Taff Merthyr carrying an updated delivery date of April 2026. Built in 1961 at English Electric’s Vulcan Foundry as D6720 and renumbered 37020 in 1974, it underlines the point of this release: the third run is not just more Class 37s, it is Accurascale digging deeper into the class’s most specific, model-worthy corners.