GWR Stella 2-4-0 Kitbash

[RosiesBoss]

Introduction

 

Readers of RMWeb may be aware of my interest in building models of locos and rolling stock that ran on the ex-Cambrian Railways part of the GWR. Refs. 7-11 describe some of them.

On page 12 of Ref. 6 is an image of a GWR Stella class, several of which were sent to central Wales towards the end of their service. I chose to model 3515, one of the last survivors, which was allocated to Brecon and which is recorded as having run with a 3000 gallon tender.

 

Some of the challenges of modelling such small prototypes include the selection of a suitable motor, how to mount it, and managing to achieve sufficient traction for the model to be able to haul a suitable load. This led me to choose between three possible systems:

1. Motor and gearbox in loco, limiting room for ballast weights for traction
2. Motorised tender pushing freewheeling loco (as described in Ref.3)
3. Motor in tender, with flexible drive to gearbox in well-ballasted loco

I selected option #3, which made use of many components already to hand in my scrapbox and among my spares. Many years ago, I completed an H0 whitemetal kit of a NSWGR Z19 class 0-6-0 that had been abandoned as “too hard” by a fellow club member. This was designed to use option #3, but came without its motor or drive shafts. Once completed, it looked like this and still runs very well:

 

My collection also includes a similarly powered Bachmann H0 “Jupiter”, so I had experience with operating and maintaining such drive systems.

 

I therefore chose to make the model from these major components (a full list is detailed below):

• Mainline Dean Goods body
• Chassis frame and gearbox from a (very sad) Rivarossi/AHM  V&TRR 4-4-0
• Tender-mounted motor
• 3000 gallon tender body from an Airfix “City of Truro” kit

The main drawing that I used is included in Ref.2. Adjusted to 4mm scale, it provided the templates used to prepare the dummy outside frames. I chose to equip the loco with a 3000 gallon tender, as used by 3515. This was a good fit for the motor chosen for this project,

 

Construction - Chassis

The Rivarossi body was dismantled:

 

 

 

The chassis was further cut down and modified to accept a Romford axle and bearings for the forward driving wheels. The rear axle bearings were moved back to correspond with the wheel spacing of the Dean Goods body, and then reinforced with 1/8” i.d. copper tube which now supports another Romford axle. The Rivarossi gear was removed from its original axle, shimmed with brass and then mounted on a splined Romford axle. In this way, the Rivarossi plastic bearings have been replaced by more durable metal ones but the rather useful gearbox has been retained. The cylinders and footplate were cut off and the remainder trimmed until it was a good fit under the (as-yet unaltered) Dean Goods body.

 

A brass front frame extension was fabricated, the design including a simple springing system which uses strips of phos bronze.

 

This assembly was then araldited to the remains of the front section of the Rivarossi chassis.

 

The original Rivarossi ballast weight was cut down to leave just the centre section that covers the drive shaft and its bearings. The Mainline weight, which fills the boiler, was shortened so that, when fitted, the body easily fits the new chassis.

 

An 8BA bolt was fitted to a drilled/tapped hole in the frame, behind the rear axle, to mount a coupling for the tender. This, in turn, was made from scrap brass tube and sheet, cut to size.

 

The Rivarossi chassis was designed to use the “American system”, ie picking up power from the wheels on one side of the loco and wheels on the other side of the tender. To this end, the plastic loco chassis had a pair of plunger pickups, which were still in good order. So, after re-positioning them to align with the bigger Romford driving wheels (and before refitting the original keeper plate), they looked like this:

 

New outside frames were made from thin copper sheet, cut to paper templates glued to the inner surface and impressed with rivet detail from behind, as detailed in Ref.12.

 

Holes for the extended axles were drilled, ensuring that these would be just a clearance fit, to facilitate alignment while setting up the mounting points between outer and inner frames.

 

 

Steps were made from brass strip and soldered to the frames. Small pieces of brass tube were soldered to the inner surface of the outer frames, halfway between the driving axles. These were positioned to locate over a 10BA threaded rod screwed through the chassis. L-shaped brass strips were soldered to the inner surface of the outer frame, just above the front steps. These were drilled to be a clearance fit over the 12BA screw which holds the front wheel/spring assembly.

 

The axle holes were then opened up. Cranks and locknuts were also fitted. The frames were fitted with a pair of axlebox/spring assemblies for the front axle, stainless steel connecting rods and a new Hornby buffer beam.

 

Dummy underhung springs were recovered from a scrapped (distorted) Hornby long-wheelbase wagon chassis. Hangers were made from copper wire, brass strip and plastic cable insulation. These were super-glued together and then glued to the dummy outside frames.

 

Construction – Body

As noted in Ref.4, most of the Dean Goods body above the footplate can be used for making a “Stella”. Here it is, as received:

 

Modifications that were made included:

• Enlarging the clearances between the wheel splashers, to accommodate the new chassis
• Reinforcing the dragbox with thin brass channel, which also provided a rear location point for the new chassis

 

• Opening up a slot in the centre of the cab footplate to clear the flexible driveshaft.

 

• Removal of front wheel splashers and redundant smokebox door fittings and restoration of gaps with thin card and epoxy cement

 

• Creation of a slot behind the footplate valence to locate the top of the outer frame.
• Relocation of sandboxes and footplate handrails

Construction - Tender

An inner chassis was made from rectangular-section, thin-walled brass tube, sculpted to hide behind the Airfix plastic tender frames. Axle holes were drilled to be a loose fit. The outer bearings (in the plastic frames) were bushed with Peco wagon bearings.

 

The coupling to loco relies on the original moulded Airfix peg.

 

To provide for the “American” pickup system, wheels on one side of each tender axle were shorted to the axle with conductive silver paint. This avoids the drag so often observed with the alternative wiper pickups – especially with non-driving wheels. Coating the inner side was insufficient, so a second application was made to the outer side.

 

The motor was bolted on top of the inner brass chassis and the wheels were fitted, including insulating washers to prevent short circuits while running.

 

The chassis was test fitted to a new Airfix tender body side, to confirm the fit.

 

Electrical connections were made to the motor and the mechanical components test run to confirm the polarity of those connections. It moved in the correct direction first time!

 

 

Mouldings for lining and handrails were removed from the Airfix body. The front moulding was reinforced around the loco-tender coupling peg with epoxy cement. A slot for the flexible drive was opened up in this component and also in the top moulding.

 

A flywheel was turned from brass stock and fitted to the motor, to provide for smoother running.

 

The body was then assembled and fitted to the inner brass chassis, after relieving any tightness in the bearings. It’s a very neat fit!

 

The loco & tender were then tested under power. Some adjustments were made to improve clearances around the flexible drive, but the rest of the mechanism worked well.

 

Finishing

Handrails, smokebox dart and sandboxes were fitted. Not much to go, now!

 

 

Front lamp brackets were glued in place, then the model was painted with Humbrol acrylic GWR green plus Humbrol enamels for the remainder of colours.

 

Home-printed cabside numbers were affixed, together with appropriate HMRS Pressfix transfers.

 

The model was then varnished with Humbrol satin clear enamel.

 

Results

 

 

Reflections

Most of this model was built from parts already to hand, either as spares, bought “just in case”, or from bits and pieces recovered from donated wrecks.

The only items bought-in for the project were:

• Dean Goods body: $56
• Romford cranks: $8.00
• Romford extended axles: $20.00
• Conductive paint: $13.95

Had I bought a Brassmasters Stella kit, plus their tender, the costs would have been GBP190 (over A$360) just for the body parts and I would have still had to pay for air mail to Oz, wheels, axles, motor, gears and gearbox.

 

I haven’t built a museum-quality model, but my example does run and haul a respectable load. I’ve enjoyed the challenges of kitbashing the body, designing and assembling my own mechanism and getting it to work. It’s been fun – and isn’t that what it’s all about?

 

Parts List

• Mainline Dean Goods body (2^nd-hand, via eBay)
• Chassis frame and gearbox from a Rivarossi /AHM  V&TRR 4-4-0 (donated wreck)
• Tender-mounted motor – Airfix MRRC Slimline (new, old stock, purchased over 30 years ago)
• Tender body from an Airfix “City of Truro” kit (new, old stock)
• Romford 21mm dia driving wheels (new, old stock)
• Romford extended axles & bearings
• 1/8” i.d. copper tube
• 16mm tender wheels – outside bearings
• Rectangular-section thin-walled brass tube
• 0.5mm copper sheet
• 0.4mm dia. phosphor bronze wire for handrails
• Brass handrail knobs
• Offcuts of copper wire and brass strip
• Heat-affected Hornby long wheelbase wagon chassis (used for its springs)
• Kemo conductive paint
• Miscellaneous BA screws, nuts & washers

References and Further Reading

1. http://www.gwr.org.uk/no-tenders.html
2. http://www.brassmasters.co.uk/Downloads/Stella%20Instructions%20parts%20list%20and%20diagrams.pdf
3. http://www.rmweb.co.uk/community/index.php?/blog/1405/entry-14843-a-tale-of-two-tenders/
4. Mike Flemming: “GWR Stella 2-4-0 – A Victorian conversion project in 4mm scale” (Railway Modeller, April 2013)
5. Anon.: “Locomotives of the Great Western Railway – Six-wheeled tender engines” (RCTS, 1956)
6. C.C.Green: “Cambrian Railways Album – 2” (Ian Allan, 1981)
7. http://www.rmweb.co.uk/community/index.php?/topic/126196-gwr-ex-cambrian-railways-large-belpaire-passenger-4-4-0-94-class/
8. http://www.rmweb.co.uk/community/index.php?/topic/88895-gwr-ex-cambrian-railways-73-class-0-6-0/
9. http://www.rmweb.co.uk/community/index.php?/topic/72460-gwr-1331-ex-whitland-cardigan-0-6-0st-project/
10. http://www.rmweb.co.uk/community/index.php?/topic/70468-gwr-absorbed-locos-on-carmarthen-junction/
11. http://www.gwr.org.uk/nocamrys5.html
12. http://www.rmweb.co.uk/community/index.php?/topic/107593-gwr-1076-class-double-framed-pannier-tank/

[rovex]

Well done. Impressive work

[Sandhole]

Proper Modelling!!

The K's outside frame Dean Goods kit is the donor loco to use if you have one!!

The outside frames are there already.

                                                   C.

[RosiesBoss]

G'day, all,

 

Thank you to all who have made encouraging comments.

 

The K's 2361 class is certainly a suitable alternative, with about the right wheelbase and underhung springs on the driven axles. Modifying the front axle would be the most significant challenge here - provided one can afford a virgin, unmade kit.

 

I have considered making one of this class from another Mainline/Hornby Dean Goods, but have decided that I will make something else. Some years ago, I put a whitemetal chassis under a Mainline Dean Goods (See Post #11 here: http://www.rmweb.co.uk/community/index.php?/topic/69067-dean-goods/.) It runs well, but is hardly distinctive.

 

I am currently getting all the bits together to rebuild this model again - into a 388 class (Armstrong Goods). Most of the outside frame details are similar to those on the 1076 0-6-0PT, so I can adapt the templates I used for my model as described here: http://www.rmweb.co.uk/community/index.php?/topic/107593-gwr-1076-class-double-framed-pannier-tank/.

 

There is a drawing in J.M.Maskelyne "Locomotives I Have Known" (Percival Marshall, 1959) of a 388 class with a round-top boiler. There are plenty of photos of those with Belpaire boilers, so reference to those should facilitate construction of an acceptable model, so "watch this space".

 

Regards,

 

Rob

 

[Mikkel]

Very nice work Rob - and thanks for the extensive write-up of how you did it.

 

Are you familiar with Mike Oxon's blog? He has also done a Stella conversion (although an earlier period). There are some pics of it at the bottom of this post:  http://www.rmweb.co.uk/community/index.php?/blog/1405/entry-14843-a-tale-of-two-tenders/

 

 

[RosiesBoss]

G'day, Mikkel,

 

Thank you for your comments. Yes, I did see Mike's blog - Reference # 3 in my story. It was helpful and inspiring.

 

Regards,

 

Rob

[Mikkel]

Ah sorry, I had missed that - and you have the RM article too I see. I wonder if there is any scope in using the Oxford Dean goods chassis for a similar project. There might be issues with the front wheelset though.

[Londontram]

Brilliant work Rob. Proper modeling in my books I love the way you've come up with good solid solutions for each step of the build.

As you say maybe not museum quality but I'm very much in the "If it looks right it is right" school of modeling and its given you a very useable model

 

Steve

[timbowilts]

Rob, this thread has inspired me to see if a Dean Goods can be converted into a 4-4-0 of the “3521” class? Some of these carried the same boiler as the Goods

 

Tim T

[RosiesBoss]

G'day, Tim,

 

I have toyed with the same idea: to use assemble a 3521 using the DG boiler/cab/footplate, but I baulked at the idea of fretting out the spindly outside frames.

 

I haven't been able to find drawings of this class, although sketches are shown here: http://www.gwr.org.uk/no440s.html and also in Jim Champ "An Introduction to Great Western Locomotive Development" (Pen & Sword Transport, 2018). There seem to be plenty of images of the class, both in books and for sale on eBay, so sorting out most details should be possible.

 

The Dean bogie could be sourced from the Triang/Hornby Dean single or the Airfix/Dapol City of Truro. The Tri-ang Nellie chassis has about the right wheelbase, as seen here with my motorised model of CoT:

 

The short wheelbase tender could be cobbled together from the Airfix/Dapol CoT kit, as described here: http://www.rmweb.co.uk/community/index.php?/blog/1405/entry-14843-a-tale-of-two-tenders/.

 

So, I guess this conversion is do-able.

 

Happy modelling!

 

Regards,

 

Rob

 

 

[DCB]

The trick missed here is driving the tender wheels as well as the loco wheels, should be possible with a ratio of very nearly 4:5 between

the wheel sizes, as in 50:1 and 40:1...

[JimC]

I haven't been able to find drawings of this class, although sketches are shown here: http://www.gwr.org.uk/no440s.html and also in Jim Champ "An Introduction to Great Western Locomotive Development" (Pen & Sword Transport, 2018). There seem to be plenty of images of the class, both in books and for sale on eBay, so sorting out most details should be possible.

There's a weight diagram in Russell, plus a drawing by Col Templar. I used those as a source for my sketches, combined with various standard parts. Now I look at it, with the benefit of having learned a bit more about how the GWR tended to lay things out, I'm a little unconvinced about the cabside as drawn in the weight diagram and I strongly suspect traced by Templar. I think a prospective modeller would be well advised to study photos of the cab sides carefully, but make sure its the right boiler variant as the cabs were very different. Of course this is Dean era GWR: there may have been more than one profile used:-) Although weight diagrams often show complex curves for the cab cutout, most photos suggest to me that cabs tended to be cut out with a small radius and a large radius, but the proportions and the intersection point varied.