Class 24: The Modelling Raison D’être

20th June 2017 by Philip Sutton

During Class 24s’ ‘Indian Summer’ on the DMU replacement turn a year later in 1978, No. 24023 spits out a black exhaust as it clatters away from Shotton Low Level with 13.30 Manchester Victoria–Llandudno on July 11th. This machine was one of only six of the type still active at the time and was only to last another two months in traffic. Picture: David Rapson

I outline the reason for the choice of the Class 24 diesel locomotive as Sutton’s Locomotive Workshop’s first project in the introductory letter that accompanies each model that is sold. In essence, the ‘Baby Sulzer’ ticked all the boxes in being geographically widespread as well as playing a vital role in the dieselisation of British Railways. To be honest though, that was only part of the reason.

Those that know me well will be aware that I am a founder member of Barrowmore Model Railway Group, based in a village on the outskirts of Chester (see It is in the Great Barrow clubrooms, with great views of the open Cheshire countryside that we maintain, enhance and build stock for our layouts. Mostyn, a 24ft by 30ft slice of the North Wales coast main line built to P4 standards is the main focus and represents the former station area and docks exchange sidings as they were in the summer of 1977. This is solidly in the corporate BR blue era (save for a few well known exceptions – 40106 being one of them), before the construction of the A55 expressway. During the high summer, heavy passenger trains and long DMU lash-ups were almost working block to block, catering for the ‘bucket and spade brigade’ visiting and returning from the North Wales seaside resorts.

Sulzer Type 2 power in action on Mostyn. As the eagle-eyed reader will spot, all the models here have been converted from the Hornby Class 25 which itself dates from the 1977 catalogue. Despite the predominance of the type in this staged view, the layout has a shortage of smaller powered locos now that the amount of rolling stock has significantly increased. Picture: David Faulkner

What many don’t realise is, at this point in time, there was strict uniformity in motive power with just four locomotive types to be seen. These comprised Classes 24, 25, 40 & 47, mostly based at Crewe Diesel Depot. The Class 37 weren’t to appear until the following year and not in any significant numbers until much later. However, on Mostyn, we have a slight issue that probably contradicts every other individual and club in the country. Having completed over 550 items of rolling stock (and a similar number still needed) we have a shortage and imbalance of locomotives! The SLW Class 24s were, in part, conceived to address this after we ruled out hacking further Hornby conversions and disregarded the Bachmann model for is inaccurate shape.

The summer of 1977 saw a dozen of the type still in service (24023/35/6/47/57/63/73/81/2/7/91 & 24133) and all were regulars through Mostyn powering a variety of traffic from humble engineers trains to priority mail services and everything in between. We already have 24047 & 24133 in the form of Hornby conversions courtesy of David Goodwin and Richard Oldfield, some of the oldest locos on the layout, which date back to 2002. The booked appearance of Mostyn at the June Chatham exhibition required all the stops to ‘pulled out’ and address the shortage of Type 2s.


Although the concept of the SLW ready-to-run Class 24 was that it was to be to ‘Mostyn standard’ out of the box, that was never going to carry much weight with my fellow club members, principally because each locomotive had an almost unique combination of details. I have chosen nine locomotives to recreate with four being prepared in time for the Chatham show in June. These were Nos. 24023/73/81/2 which exhibit differences that include size and shape of boiler and fuel tanks, roof top exhaust panel shrouding, radio communication sockets, and even the way the yellow warning panel was applied. No. 24073 was the oddball, an ex-Scottish loco resurrected from store.  It had centrally-mounted headcode discs on the plated nose section as a result of being been shopped at Glasgow Works. These distinctive points were all incorporated into the resulting models although it is unlikely that anyone bar the most hardcore Class 24 fan will have noticed. I was also trialling some of my own in-house etched components to see if they can be incorporated in future models but I don’t think they are going to be durable enough for retail. A more comprehensive description of the work undertaken, including refined weathering, will be recounted in due course.

No. 24081 at work on Mostyn, propelling a van train down the exchange sidings. During 1977, this loco was no more interesting than any of the others – it’s celebrity status only came two years later when it survived to become the last of class in service. Note the yellow painting of the quarter-light as a result of a spank on the cab corner, a repair feature that only existed for the second half of the year.

During the days before set up, the locos were allocated to specific trains. No. 24023 got the 2D53 Crewe-Bangor DMU replacement short rake of Mk. 1s; No. 24073 the new Sulphur hoppers, No. 24081 on a new box van train and No. 24082 taking over a Down ballast. The second of these locos had the toughest test with the kit/scratchbuilt hoppers, which were required to negotiate some of the most complex trackwork on the layout including numerous crossovers and a double slip both hauling and propelling long rakes. All locomotives performed faultlessly (they are all supercapacitor fitted) and I don’t think that I’m out of order in saying they were a revelation in terms of reliability and performance despite the fact that some CV settings had to be adjusted to ensure all operators were confident in their response compared to older motive power. By the end of the weekend, even our newest drivers (and a guest 7 year-old) had smiles on their faces and were using all the sounds and features without a second thought. Here’s a shot video I managed to shoot with my smartphone – feel free to share it.

A compilation of SLW Class 24 sound action on Mostyn during the Chatham exhibition.


It is really great to see that others are starting to appreciate the model and are making modifications to personalise them to their own specific requirements. My friend Paul James has taken it to the extreme by turning the clock forward on his first built D5000 to bring into the blue 1970s pre-TOPS era and dropping the ‘D’. Look out for pictures on  Mark Tatlow has also let me know about the good progress on his model that will see use on his impressive Kyle of Lochalsh line inspired Portchullin layout. See his June 12th posting at

More and more people are finding the courage to make changes and weather their SLW Class 24s to suit their own requirements. Although more versions have just been announced it is unlikely that we will be able to cover every single specific variation so we encourage people to get carving and painting. This is Paul James’s No. 5000 earning it’s keep on Greg Brookes’s Shenston Road EM gauge layout.


The word is clearly out and more and more publications are taking a genuine interest in the Class 24 and it’s ground-breaking features. There have been several glowing reports in Scalefour News, the journal of the Scalefour Society, and the latest issue (July 2016) of Railway Modeller has given over no less than four pages to SLW and the model! Editor Steve Flint, who describes himself as a DCC sound Luddite was instantly won over as we talked at length about his BR blue interest – remember his Kyle of Tongue layout? Tim Rayner revealed that we had broken the haulage test record on Peco’s in-house layout. How about this quote from a publication that is sometimes regarded as playing it safe with reviews – “For the record, the DCC Sound Class 24s are simply the finest 4mm scale models we have heard. It has truly raised the bar and is simply unbeatable in terms of bang for buck”.

The July 2016 issue of Railway Modeller magazine includes a two-page review of the models, plus a further two page interview examining the Sutton’s Locomotive Workshop philosophy.


You will now be aware that we launched a further two variants in mid-June, comprising a pilot scheme loco in standard BR green with experimental Athermos axleboxes (No. D5016); and a ‘run of the mill’ late BR blue example with Class 25-style sandboxes (No. 24063). These are in stock and available to order immediately on 01780 470086.

ZIMO sound expert Paul Chetter will also have a variety of Class 24s on display as part of his DCC demonstration stand at the Perth model railway exhibition this weekend (June 25th & 26th) and will be more than happy to explain all the amazing DCC features and sound nuances for you if you ask nicely.

Until next time. Happy modelling!


Philip Sutton