🚆 Accurascale Announce New OO Gauge Class 37/9 Locomotives

Following on from their recent announcement of new Class 37/4 subclass locomotives, Accurascale have announced a further run of two new models - showcasing 37/9 Mirlees-engined variants for the first time ever in OO Gauge!

While Accurascale boldly took on the EE Type 3 as a project, it principally concentrated on variants never produced before on OO/4mm ready-to-run models, offering modellers an even more diverse choice in an already legendary varying locomotive. This latest release of the Mirrlees powered 37/9 is sticking true to the principles of breaking new Class 37 ground as they go somewhere that no manufacturer has been before. Two of the Mirrlees examples will be available covering much of the life of the sub class, from original conversion, through their classic late sectorisation period.

A comprehensive new sound project has been recorded with assistance from Europhoenix and UK Rail Leasing. The final models are expected to arrive during Q4 2025.

Their previously announced new batch of Class 37/4 locomotives, also detailed below, comprises of five new examples in BR large logo blue, Railfreight, EWS and Colas Rail Freight liveries. These models feature an updated tooling to cover the 37/4 as well as some tweaks to the operable roof fan, DCC systems and body details. We also expect these to arrive during Q4 2025. 

Building on the already class leading specification of the existing Accurascale Class 37s, this new production run sees all new tooling to cater for the Class 37/4 variant (and other future variants!) which now includes the operating roof fan which is synced to the DCC sound file and also operates on DC. With subtle tweaks around the bonnet top doors, improved glazing fitment to stop them popping out in rough handing through the postal/courier systems, grille tweaks, and building on the already impressive drive train and sound set up, the ultimate Class 37 in OO/4mm gauge has taken another step forward from the competition.

General Class 37 Background

The Class 37 (aka English Electric Type 3) were produced as part of British Rail’s modernisation plan. They became a very familiar sight across the network, in particular forming the main motive power for InterCity services in East Anglia and Scotland and performed well on other secondary routes and regional services for many years. Despite being over 50 years old, the class are still in use to this day - with over 60 in active use on passenger, freight and departmental duties as well as 30 preserved examples.

 (Information provided via Wikipedia) 

Class 37/9 History

Introduced in 1986-7, the repowered Class 37/9s were an off-shoot of the ill-fated ‘Class 38’ project, a proposed 1,800-2,250hp Class 31/33/37 replacement with the haulage capability of a Class 56 or 58. As many as 500 units were planned, which attracted significant interest from locomotive builders and engine manufacturers from the UK, Europe and the USA. Two British manufacturers quickly established themselves among the front runners with engine designs that boasted incredible fuel efficiency.

The Mirrlees Blackstone MB275T from Hawker Siddeley and the Ruston RK270T from GEC Transportation, could both develop over 2,000hp from a straight six cylinder layout, providing a significant reduction in maintenance costs. Having both passed BR’s punishing approval process, a further further two-year trial was undertaken using six Class 37 donors that were undergoing ‘refurbishment’ at BREL Crewe Works. As the Mirrlees unit was slightly heavier than the English Electric 12CSVT they were replacing, they were included in the 120-tonne ballasted group, otherwise known as ‘heavyweights’.

Hawker Siddeley offered four engines for Nos. 37901-4 and these were mated to a Brush BA1005A alternator, while the Ruston in Nos. 37905/6 was partnered with GEC G546AZ electrical equipment. Both engines were set to deliver just 1,800hp to avoid overloading the existing EE traction motors. There were external modifications too. The Mirrlees unit with silencer was longer and taller than unit it replaced, resulting in a new ‘peaked’ roof, while the Ruston, which tipped the scales at just 13.75 tons, also featured a revised roof to accommodate a new silencer layout.

The first pair, Nos. 37901/2 (ex-37150 and 37148), left Crewe at the end of October 1986, while the two Rustons (ex-37136 and 37206) were completed by mid-December. Nos. 37903 (ex-37249) and 37904 (ex-37125) followed in February and April 1987 respectively. Cardiff Canton was chosen to look after the small fleet and these were allocated to the Metals sub-sector for local steel operations, although they were also fitted with slow-speed control for coal duties. All were delivered in Railfreight grey, with No. 37901 quickly being named Mirrlees Pioneer and No. 37905 Vulcan Enterprise.

The Class 37/9s quickly found their feet, despite being intensively diagrammed, and working in pairs had no problem taking over from the double-headed Class 56s on the 3,060-tonne Port Talbot-Llanwern iron ore trains. However, they were found to load much more slowly leading to the ‘slug’ nickname for the class. Their reliability was also impressive, although some issues were experienced with both the turbochargers and the silencer configurations on both designs. The latter resulted in both types receiving modified roof layouts.

Unfortunately, the ‘Class 38’ project was cancelled in December 1987. Despite this setback, BR chose to purchase the engines rather than return them to standard condition. Happily, the incredible fuel efficiency and extended maintenance periodicity displayed by the Mirrlees design likely contributed to Brush winning the Class 60 contract in 1988, and this was specified with the eight-cylinder version of the power unit.

By August 1988, Nos. 37903/6 had both been outshopped in the new triple-grey Metals scheme, with Nos. 37904/5 being similarly repainted in 1990 and Nos. 37901/2 in March 1991, by which point the fleet was beginning to wander much further afield. However, it wasn’t long before their non-standard nature began to count against them and nearly all spent periods in store during the 1990s. While all six passed to Trainload Freight South West / Transrail in 1994, with Nos. 37901/6 also receiving big ‘T’ logos, No. 37904 was the first to be permanently stopped at Canton in April 1996.

The resurgence of freight in the early EWS era saw regular work return for the remaining quintet, but with Class 66s starting to arrive the inevitable was held off only until November and December 1998 when Nos. 37901 and 37903/5 were also sidelined. The final pair, Nos. 37902/6, were switched off in January 1999, although unofficially named No. 37906 Star of the East was reprieved as part of the EWS ‘heritage fleet’ for galas and open days and was even repainted back into Railfreight grey ahead of the Old Oak Common open day in August 2000.

No. 37903 was scrapped at Crewe Diesel in October 2005, while No. 37904 suffered the same fate at CF Booth, Rotherham, in November 2004. No. 37902 was acquired by Direct Rail Services in 2002, which then disposed of it to Sims Metals, Beeston, in April 2005 after cancelling its overhaul. Happily, No. 37901 was saved in 2003 and was a regular performer in preservation before being acquired by Colas Rail and then Europhoenix in 2016 and gaining the operator’s house colours. It subsequently returned to main line operations in 2022 for the EP Rail ‘spot hire’ subsidiary and was recently repainted back into Railfreight Metals livery. The two Ruston locos also both worked in preservation at various points over the last 20 years, although they are now owned by UK Rail Leasing and are undergoing a slow return back to operational, albeit non main line, condition.