16mm Projects

Gerv Wright's Merlin WLLR No 14


(photo courtesy of John Kithenman)

The full size loco has long been a favourite of mine. To my eyes it is a good looking machine and I have many enjoyable journeys behind it. I also feel an affinity with the loco as it was ‘born’ in Leeds in 1954 so we have that in common.

As is well known the engine was built for the Sierra Leone Railways being repatriated in 1975. The design itself originates from 1898 and aside from being enlarged (boiler and cylinders) from 1903 continued to be built up to 1954 when WLLR14/SLR85 and her sister were the last two built. Elements of the design were used in the production of ‘Leeds No 1’ in 1902, for ‘Russell’ in 1906 and others. (The Hunslet Engine Works – D H Townsley – Plateway Press)

So when the opportunity came to purchase a second hand model built by Merlin I grabbed it. Somewhat typically a few months later Accucraft announced they were to make a new model – so I vowed to make my Merlin look and operate to my satisfaction or I’d have to get the cheque book out again!

I fully expected to have significant work to do and here is a list of what I’ve done:-


  • Regulator/Lubricator - On first steaming the boiler wouldn’t go above 30 psi (it’s designed for 50 psi) due to the combined regulator and lubricator leaking – it’s built from two pieces and the seal between the two was blown - also leaking oil and water/steam into the adjacent box containing the batteries and rc receiver! Truing of the mating surfaces and using liquid gasket cured this but steam was clearing leaking past the regulator which also suffered from sticking. The later was caused by a protruding roll pin but the former took some time to cure. The two circular surfaces forming the regulator were first under suspicion but when no amount of flatting the surfaces cured the problem further investigation was necessary. I discovered that steam was able to bypass the regulator because the hole for the outlet was too deep and breached the regulator shaft. This was fixed by making a lining for the regulator shaft and a new regulator rod – this also cured excessive wear in the fork at its end.
  • Cylinders and valves – the engine had no compression when rotating by hand. Investigation showed that the pistons were plastic which I believe were original. Because of the design I imagine that with steam pressure they would seal to some extent but I decided to make new brass pistons with O rings. The next steaming blew the O rings on the inlet pipes and after these were replaced the piston valves leaked. Use of 640 steam oil reduced the leakage to a whisper on one side only but as luck would have it the opportunity came to purchase a brand new set of valves via Anything Narrow Gauge.
  • Side rods – excessive wear in these was taken out by reaming the four offending holes round and bushing.
  • Regulator servo – located at the front of the right hand tank the control rod was the length of the tank passing over the batteries and receiver and because of its length flexed. I relocated it next to regulator and pushed the electrics forward.
  • Radio – the loco came with a 27 mhz rc which I replaced with a 2.4 ghz set.


The loco runs very well but did have a tendency for the regulator to be all or nothing. A combination of finer control from the new rc and feathering the regulator ports has made it very controllable.


  • Cab door opening – The cut out in the side was the wrong profile so this was filed to a more prototypical shape with the door opening extended to the bottom of the side and new handrails made. The D section which extended across the cab side was cut back to the tank top.
  •  Sun roof - All my photos of the loco show the ‘sun roof’ in the cab open so I decided that as this was a feature that needed to be modelled. The roof can be left propped up or dropped down.
  • Cab windows - Swift Sixteen rotating cab windows fitted the existing cut outs but I filed down the inner sections as they were far too thick.
  • Tank tops – The existing coal bunkers & tank fillers were replaced as I felt the existing ones were not close enough to scale. I also made sand boxes and their control linkage.
  • Tank fronts – the profile of the tank front next to the smokebox was altered to make it more closely resemble the original, hand grabs were put on the tank tops and a step on the left hand tank front.
  • Smokebox – The smokebox door was too large so this was turned down and new hinges made. The smokebox handrail was relocated closer to the reduced door and the old holes filled.
  • Lights – these were Roundhouse DHR ones turned down with brackets made from brass sheet. The conduit to the front lamp was also modelled.
  • Cowcatchers – made up from brass section.
  • Cab steps – from brass sheet
  • Slide bars – these fell apart from there fixings and as they were made of round bar and rather shiny I decided to replace them with a rectangular section.
  • Bogies – the width between the dummy sideframes was reduced and sloping axleboxes added (butchered from Accucraft L & B wagon boxes).
  • Livery & plates – Whilst I like black, I have too many black locos already and also it would mean modelling the extended tanks which I don’t like. On the WLLR it has also run in green, red & blue. I choose to repaint the loco in green using Halfords spray enamel. This livery on the WLLR was a representation of the pre-war SLR livery. The plates were supplied by Narrow Planet.

There are still a few details I’m considering adding but I’m now happy that the loco looks the part and I’ll find it interesting to compare it to the Accucraft model when it appears.

This is a close up of the cab opening. At this stage the D section across the cab side has been removed but the cab is as bought.

A close up of the new cab opening profile.

A view of the detail added to the tank top.

A view of the whole loco to compare with photo 1.

and steaming on Lawnswood Light Railway 2015

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