Rhymney Railway Class K 0-6-2PT

[RosiesBoss]

Introduction

This project was planned to make use of existing bits and pieces in my scrapbox wherever possible, to minimise costs.

The design chosen this time is the Rhymney Railway Class K, as reconstructed by the GWR as a pannier tank. References 1 to 4 were useful here, as were images published from time to time on eBay and in Ref.5. I chose to model GWR 136, for which several images were available. This design, of course, has the complication and challenge of double frames – always fascinating to watch when in motion. No kits or RTR models seem to be available for this design.

 

For this project, drawings of the frames, cab and bunker were sourced from Ref.4. The rest was gleaned from photos.

 

Construction – Chassis

The wheelbase for this loco was 7’1”+8’2”+5’9”. I could find no RTR chassis with those dimensions, so everything had to be scratchbuilt.

A simple inner chassis was marked up on 12mm square brass tube.

 

Driving axle holes were drilled and then adjusted with soldered washers until they were square and in line. The chassis was then trimmed front and rear, using the rear offcut to make a simple pony truck. Romford and Gibson wheels were fitted temporarily to facilitate fine adjustments and ensure reliable running.

 

Outside cranks were fabricated from brass strip and 12 BA screws, using a Romford one as a pattern:

 

 

 

Gibson universal coupling rods were then fitted:

 

Holes were opened over and under the front axle for the gearbox, which was then fitted and connected to the motor with a short piece of silicone rubber tube. After checking that everything ran sweetly and that motor polarity was correct, the motor was fixed to the chassis with silicone bathroom sealant. This technique acoustically isolates the motor from the frames to eliminate the “tuning fork” effect that makes some models very noisy.

 

 

Pickups were then fitted and adjusted until the chassis ran sweetly

 

A tension-lock coupling was fitted later to the pony truck.

 

Construction – Body

The footplate was fretted out of .015” copper sheet, with provision for attachment to the chassis including an 8BA bolt for the front tension-lock coupling.

 

 

Buffer beams were prepared and attached. Paper templates were cut from a 4mm scale drawing of the loco (Ref.4) and glued to copper sheet. Once the glue had set, the copper was roughly cut to size:

 

Once all parts were accurately trimmed, they were soldered to the footplate:

 

Wheel splashers, steps, cab rear shelf and bunker back were cut from thin brass and soldered into place.

 

The pannier tanks are a challenge to model convincingly on many GWR classes – and this was no exception. I had wanted to re-purpose the tanks of an old Hornby 8750 class loco, but these turned out to be nearly 2mm too wide overall when offered up to the copper/brass body made to the drawings. A suitable alternative was found in a free 3D modelling file for a 1:48 model (Ref.6). The tank/boiler file was re-sized to 1:76 scale and printed.

 

Cleaned up and assembled, it didn’t look too bad and was ready for the firebox, lower smokebox and other details to be added.

 

 

Loose assembled on footplate after injectors had been added:

 

Springs were recovered from a redundant Hornby Ivatt 2-6-0 tender frame:

 

 

Simple axleboxes were prepared from polystyrene sheet.

 

The bunker extension and buffers were then added. Dry-assembled with tanks and chassis:

 

Cab beading, backhead, reversing lever, splashers, springs, handbrake added:

 

Smokebox dart, scale couplings, sandboxes, handrails, brass chimney and injector pipes added:

 

Final details: Cab roof, inc. whistles & vent; handrails on top, front of tanks; steps on front of tanks; brackets; vac pipes, including those under footplate:

 

 

Finishing

I chose to finish the model unlettered, in GWR green, inspired by the image of 136 in Ref 3.

 

Results

 

Here is 136 again, doing what she was made for, with 152 passing, doing the same:

 

Parts List

·         3D printed 57XX class pannier tank body (Ref.6)

·         3D printed injectors

·         Tender frames from Hornby Ivatt 2MT– for springs

·         Hornby backhead (L5436)

·         Romford 18mm dia driving wheels

·         Romford extended axles

·         Home-made outside cranks

·         Gibson 14mm trailing wheels

·         Gibson coupling rod kit

·         Brass & copper sheet

·         Evergreen polystyrene sheet and strips

·         Handrail knobs – Commercial brass from Casula Hobbies

·         0.4mm phosphor bronze wire for handrails and pickups

·         Motor: Hornby Type 7 Mabuchi

·         NWSL 142-6 gearbox

·         Silicone rubber tubing to couple motor to gearbox

·         Whistles – Peter’s Spares

·         Cast brass chimney – from scrapbox

·         Square-section brass tube for inner chassis

·         Buffers – H0 NSWGR from Casula Hobbies

·         Couplings

·         Guitar E string for vac pipes

·         Staples for lamp brackets

·         Printed circuit board for pickups

·         Misc BA screws and nuts

 

References & Further Reading

1.       RCTS “The Locomotives of the Great Western Railway – Part 10 – Absorbed Engines1922-1947 (RCTS, 1966)

2.       J.H.Russell: “A Pictorial Record of Great Western Absorbed Engines” (OPC, 1978)

3.       Mike Romans et al.: “Locomotives Illustrated  66: Great Western 0-6-2Ts” (Ian Allen, Jul-Aug 1989)

4.       Railway Modeller, Oct 1991

5.       https://www.rmweb.co.uk/blogs/entry/25015-rhymney-railway-k-class-0-6-2st0-6-2pt/

6.       https://www.thingiverse.com/thing:3828506

[Mikkel]

Very nice result, as always. I do like the combination of multiple modelling media: Brass kit, RTR, 3D printed, styrene. Highly creative. Fit in a whitemetal kit and some wood too in the next one and you've got a full house!

[JimC]

Nice. I find them quite intriguing as a pannier tank because they look rather unexpected to me somehow. Sort of unbalanced, but I'm not sure I could actually tell you why. Good to see a model, wish I had the skills. 

 

If you'd contacted me I would have done you a larger version of my sketch and a vector file. As I recall I had to do a fair bit of educated guesswork for my sketch, be interesting to see how much my interpretation and yours differed. 

 

That goes for anyone looking at my blog sketches for a model: contact me and I'll send you a larger sketch and anything I can remember about decisions drawing it. 

Edited June 1, 2023 by JimC

[corneliuslundie]

Nice to see. I have a model of a K class as built, put together for me by a friend from a kit which (probably fortunately in view of the problems he had) is no longer available.

In case anyone is interested there is a 7 mm/ft drawing of the class as built in "Welsh Railways records Volume 1: Rhymney Railway drawings" by Nigel Nicholson, Trefor Jones and Mike Morton Lloyd (Lightmoor Press with the WRRC, 2010). Also a nice photo of No, 122 (ex RR 85).

I really must have a go at the kit (from the same source) for the J class 0-6-0ST some time, when I am feeling brave,

Jonathan

[JimC]

1 hour ago, corneliuslundie said:

"Welsh Railways records Volume 1: Rhymney Railway drawings" by Nigel Nicholson, Trefor Jones and Mike Morton Lloyd (Lightmoor Press with the WRRC, 2010).

Which is an excellent volume, firmly recommended, and was invaluable when working out my RR sketches. Sadly, though, no drawing of the pannier tank version.

 

 

 

Edited June 1, 2023 by JimC

[corneliuslundie]

Yes, Mike Lloyd and Trefor Jones never drew the version rebuilt with pannier tanks, though No, 122 has them in the photo.

Jonathan