GWR 3901 class 2-6-2T

[RosiesBoss]

Disclaimer

This project is one that includes more than a few compromises! It didn’t produce a fine-scale model, accurate in all respects. Rather, it was just an amusing diversion. Rivet-counters beware!

 

Introduction

I’ve been familiar with the Tri-ang Princess class chassis since I was given my first train set in Christmas 1955. Despite many years of “love” and a couple of repaints, the loco still runs:

 

Consequently, when someone gave me an incomplete Princess chassis frame, found under their new house, I gladly added it to my spares box, awaiting inspiration for another day. The wheelbase is not far off that needed for a GWR 39XX. I had plenty of sheet brass and copper, Romford wheels, axles and gears, so began this challenge.

 

For those wishing to do something similar, but in plastic, there was a suitable construction article in Ref.9.

 

Parts List

·         Early Tri-ang Princess chassis block (Ref.1) and coupling rods

·         Romford wheels, axles, gears & bearings

·         Tri-ang X04 motor

·         MRRC 5-pole armature

·         Comet LS2 pony truck kits

·         Alan Gibson 4839H pony truck wheels

·         Re-purposed 2nd hand camera springs

·         Airfix City of Truro boiler

·         Sandboxes from scrapped Tri-ang Dean Single

·         3D-printed injectors

·         Brass & copper sheet

·         H0 NSWGR buffers & scale couplings

·         Markits handrail knobs

·         0.45mm phosphor bronze wire

·         Humbrol & Tamiya enamels and acrylics

·         Jackson-Evans etched number plates

·         CAL-SCALE 190-606 HO Whistle

 

Construction

Unmodified Princess frame, with 4mm scale drawing:

 

Modified frame with new wheels, gears, coupling rods, pickups and rebuilt X04 motor:

 

Pony trucks:

 

Initial fit test of pony trucks:

 

Trimmed, mounted and sprung:

 

Footplate, valences & buffer beams:

 

 

Paper templates (from Ref.2) attached to copper sheet and roughed-out:

 

Assembled onto footplate after trimming:

 

Boiler before & after surgery:

 

 

Boiler test fitted to model:

 

Cab roof & steps fitted roughly – model ready for detailing:

 

Details added:

 

Results

 

 

3917 passing 4508 (Crownline/Lima) and 8103 (rebuilt Grafar):

 

References & Further Reading

1.       http://www.hornbyguide.com/service_sheet_details.asp?sheetid=334

2.       Railway Modeller, Nov 1967

3.       Model Railways, Apr 1975

4.       www.greatwestern.org.uk/drawings/loco/loco121.jpg

5.       https://www.devboats.co.uk/gwdrawings/gwrstandardboilers.php

6.       Jim Champ: “An Introduction to Great Western Locomotive Development” (Pen & Sword Transport, 2018)

7.       Locomotives Illustrated No.33: “The Great Western Railway’s 2-6-2Ts” (Ian Allan, 1983)

8.       Anon.: “The Locomotives of the Great Western Railway: Part 5 – Six-Coupled Tank Engines” (RCTS, 1958)

9.       Railway Modeller, Apr 1976

[Paul H Vigor]

9 hours ago, RosiesBoss said:

Disclaimer

This project is one that includes more than a few compromises! It didn’t produce a fine-scale model, accurate in all respects. Rather, it was just an amusing diversion. Rivet-counters beware!

 

Introduction

I’ve been familiar with the Tri-ang Princess class chassis since I was given my first train set in Christmas 1955. Despite many years of “love” and a couple of repaints, the loco still runs:

 

Consequently, when someone gave me an incomplete Princess chassis frame, found under their new house, I gladly added it to my spares box, awaiting inspiration for another day. The wheelbase is not far off that needed for a GWR 39XX. I had plenty of sheet brass and copper, Romford wheels, axles and gears, so began this challenge.

 

For those wishing to do something similar, but in plastic, there was a suitable construction article in Ref.9.

 

Parts List

·         Early Tri-ang Princess chassis block (Ref.1) and coupling rods

·         Romford wheels, axles, gears & bearings

·         Tri-ang X04 motor

·         MRRC 5-pole armature

·         Comet LS2 pony truck kits

·         Alan Gibson 4839H pony truck wheels

·         Re-purposed 2nd hand camera springs

·         Airfix City of Truro boiler

·         Sandboxes from scrapped Tri-ang Dean Single

·         3D-printed injectors

·         Brass & copper sheet

·         H0 NSWGR buffers & scale couplings

·         Markits handrail knobs

·         0.45mm phosphor bronze wire

·         Humbrol & Tamiya enamels and acrylics

·         Jackson-Evans etched number plates

·         CAL-SCALE 190-606 HO Whistle

 

Construction

Unmodified Princess frame, with 4mm scale drawing:

 

Modified frame with new wheels, gears, coupling rods, pickups and rebuilt X04 motor:

 

Pony trucks:

 

Initial fit test of pony trucks:

 

Trimmed, mounted and sprung:

 

Footplate, valences & buffer beams:

 

 

Paper templates (from Ref.2) attached to copper sheet and roughed-out:

 

Assembled onto footplate after trimming:

 

Boiler before & after surgery:

 

 

Boiler test fitted to model:

 

Cab roof & steps fitted roughly – model ready for detailing:

 

Details added:

 

Results

 

 

3917 passing 4508 (Crownline/Lima) and 8103 (rebuilt Grafar):

 

References & Further Reading

1.       http://www.hornbyguide.com/service_sheet_details.asp?sheetid=334

2.       Railway Modeller, Nov 1967

3.       Model Railways, Apr 1975

4.       www.greatwestern.org.uk/drawings/loco/loco121.jpg

5.       https://www.devboats.co.uk/gwdrawings/gwrstandardboilers.php

6.       Jim Champ: “An Introduction to Great Western Locomotive Development” (Pen & Sword Transport, 2018)

7.       Locomotives Illustrated No.33: “The Great Western Railway’s 2-6-2Ts” (Ian Allan, 1983)

8.       Anon.: “The Locomotives of the Great Western Railway: Part 5 – Six-Coupled Tank Engines” (RCTS, 1958)

9.       Railway Modeller, Apr 1976

They appear very tall locos? Looking at photos I can't decide if this is/was an optical illusion? The loading gauge was set.

Edited April 15 by Paul H Vigor
to add information

[RosiesBoss]

G'day, Paul,

 

This drawing of the class in their final form shows they made full use of the loading gauge: www.greatwestern.org.uk/drawings/loco/loco121.jpg

 

Regards,

 

Rob

[DCB]

The 3901 was one of Churchward's few failures.   He saw the French compounds, thought I can do better than that, and made the Saints, they pulled better but rode worse so he built the Stars, and then when everyone else had moved to Atlantics and 4-6-0s he said "Bring it on," and built the "Bear"    He saw LNWR 2-8-0s and built the 97 and the 28XX, much better, but when Hoy on the L&Y brought out his 2-6-2 T which was supremely ugly Churchward said "I can do uglier than that"  but failed (Just).
 

The 3901 was on paper a rebuild of 1890s 2301 class Dean Goods locos.   Churchward wanted to build 45XX but new build money (capital) was not forthcoming so he used the repair fund to "Rebuild" Dean Goods retaining  the wheels, /cylinders / motion etc with Churchward's 44/45/46XX  tiny Std no 5 boiler and a 45XX cab and the ugliest tanks he could devise.   Even though the 1890s Dean boiler was not as good as the final 2301 or indeed its progeny the 57XX there can be little doubt it was a better steamer than the std no 5.  It's so much bigger.  and the final 2301 boiler was much better than the Ivatt 2MT boiler when tested in the 1950 when they tried to replace 2301 with Ivatt and 78000 2-6-0s

 

On 15/04/2024 at 10:12, Paul H Vigor said:

They appear very tall locos? Looking at photos I can't decide if this is/was an optical illusion? The loading gauge was set.

 

 They were as were the 42XX   56XX  31XX  3150 etc ,    But lets face it who checks the height of their locos from rail level  apart from me as my clearances are minimal and ridiculously over height Hornby King and 2721 won't fit my hidden sidings.

But caveat time.   Churchward locos had wooden cab roofs overlaid with (tarred?) canvas.    Collett changed this to steel sheets which lowered the roof, most dramatically in the new build Prairies starting 6100 which earlier locos were altered to conform, but even the 42/56/72 XX had this change.  It affects the cab eaves which almost every model gets wrong, Bachmann 56XX  spectacularly so, as the drawings would not have changed.  Changes started circa 1929(?) and were unpopular with enginemen from my reading of Engineman's reminiscences.
The model has the Airfix City of Truro boiler.   The Airfix smokebox  is too big in diameter for a std no 2 and too small for a std no 4 and is much larger than the std 5.  45XX   That sort of hurts the illusion, massive loco tiny boiler.   as do the photographs with the 45XX (should be same boiler) and 81XX (built 5 years after last 3901 scrapped)   which  emphasises the issue.
For me the lack of curved drop ends to the footplate is noticeable but lets face it you would need to be around 100 to remember them so full marks for creating something different.

[RosiesBoss]

Thank you, DCB, for your observations.

 

I agree that, in my model, the boiler is a bit larger than it should have been. Ref.5 in my build account shows the Std.5 smokebox (3901 class) to have been 4’2” dia and the Std.4 smokebox (City class) to have been 4’11” dia. In model form, this resulted in my model smokebox diameter being oversize by 3mm. I accepted that, as I have not yet mastered the skills required to fabricate a GWR taper boiler.

 

While researching the model, I prepared an overlay drawing of the 3901 and 45XX classes, aligning the boilers so as to work out whether it was feasible to rebuild a 45XX body.

 

It’s clear that the height of the smokebox centrelines are different: 3901: 8’3”; 45XX: 7’6”. The 3901s were significantly taller. It was also clear that the straight footplate of the 3901 was very different to that of the 45XX which had a drop front end. Had I been able to find a second-hand 45XX to rebuild, I wouldn’t have used much more than part of the boiler. (What a waste!)

 

Apart from the boiler, I did make other compromises:

·         The correct driving wheelbase should be 7’0”+7’0”; the donor chassis was 6’6”+6’6”.

·         Chimney & safety valve cover were’nt perfect, deriving from the Std.4 boiler.

·         Rivet detail was absent.

·         No cab interior was fitted.

 

As I stated in the disclaimer, this was never meant to be a perfect model – just one that gave enormous pleasure to make and run.

 

As for the anomalous presence of 8103 in one of my images, let me refer you to modellers’ Rule No.1…..

 

Regards,

Rob

[brumtb]

Following on the 45xx route, here is my 39xx using a Bachmann 45xx. As usual there are compromises e.g. the driving wheels are smaller but it is very useful for my Birmingham area based layout.

Tony

[tomparryharry]

I'll be following this thread with interest. I would have thought that a Dean Goods model might be the ideal starting point, having the right size wheels, and the brake rigging. 

 

I'm off to have a look at the OPC books, Dean Goods to 39xx. Wheels, spacing, etc. 

[Steamport Southport]

4 hours ago, tomparryharry said:

I'll be following this thread with interest. I would have thought that a Dean Goods model might be the ideal starting point, having the right size wheels, and the brake rigging. 

 

I'm off to have a look at the OPC books, Dean Goods to 39xx. Wheels, spacing, etc. 

 

It was just a Dean Goods with a new boiler, tanks/cab/bunker and pony wheels as a temporary measure before they had built enough Large Prairies as the 2-4-2Ts were underpowered. I think that First World War then got in the way of building replacements.

 

The Dean Goods were virtually obsolete anyway. They would have all been gone well before 1940 if WWII hadn't happened.

 

So a DG chassis* would be the best starting place unless you can find the "rare as hens teeth" Jackson Evans kit. I don't think I've even seen one come up on eBay.

 

 

Decent drawings and article on modelling them in Railway Modeller in the Mid 1970s as part of the series by Group Captain Brian Huxley.

 

Google is suggesting April 1976.

 

 

*Choices are Oxford if RTR, and High Level or Comet if using etched chassis

 

 

Jason

[lofty1966]

4 hours ago, Steamport Southport said:

 

It was just a Dean Goods with a new boiler, tanks/cab/bunker and pony wheels as a temporary measure before they had built enough Large Prairies as the 2-4-2Ts were underpowered. I think that First World War then got in the way of building replacements.

 

The Dean Goods were virtually obsolete anyway. They would have all been gone well before 1940 if WWII hadn't happened.

 

So a DG chassis* would be the best starting place unless you can find the "rare as hens teeth" Jackson Evans kit. I don't think I've even seen one come up on eBay.

 

 

Decent drawings and article on modelling them in Railway Modeller in the Mid 1970s as part of the series by Group Captain Brian Huxley.

 

Google is suggesting April 1976.

 

 

*Choices are Oxford if RTR, and High Level or Comet if using etched chassis

 

 

Jason

Been two JE unstarted kits in the last 12 months.

Mega money!

Would love to know who has the artwork for them.

[Steamport Southport]

Must have missed them!

 

I wonder whether Phoenix have them stashed away somewhere.

 

Alas I wouldn't pay over the odds for things, but it's one of the kits that I do try and keep an eye out for if they are reasonably priced. 

 

The others are all from M&L - The Great Bear, Dean Single and LNWR Cornwall (preferably with the inspection coupe). None of which really fits into anything I would model. I just like them. Apparently the tooling for all of them are either knackered or lost.

 

Certainly seen The Great Bear sell for well over £400!

 

 

Jason

[RosiesBoss]

G'day everyone,

 

I didn't use a Dean Goods as a starting point for several reasons:

1. The only DG chassis I had were plastic Mainline ones left over from other projects - too flimsy.

2. The DG wheelbase is 7'3"+8''3" - too far away from the 3901's 7’0”+7’0”. The Tri-ang wheelbase was much closer.

3. DG wheels were 4'6" dia: much smaller than the 3901's 5'2"

 

There wasn't much (if anything) that I found re-usable in a DG. Hence the decision to (largely) scratchbuild.

 

Regards,

 

Rob

[brumtb]

The Dean Goods drivers were actually 5' 2" although as you say the 39xx wheelbase differed from the DG.

I wonder how much of the DG was actually reused really.

Tony

[RosiesBoss]

My apologies to all for my blunder over DG wheel sizes! What was I thinking?

 

Early in my preparation for this project, I did, in fact, consider using discarded Mainline DG wheels, but with plastic centres and 3mm dia axles, they didn't fit well with my plans to use Romford 1/8" bearings and gears or Markits crankpins that needed to be soldered.

 

Thank you to everyone who has shown interest in this project.

 

Regards,

 

Rob

[JimC]

On 22/04/2024 at 08:36, brumtb said:

The Dean Goods drivers were actually 5' 2" although as you say the 39xx wheelbase differed from the DG.

I wonder how much of the DG was actually reused really.

Tony

The story I heard was that Swindon was short of capacity in the machining shops at the time, so reusing the Dean Goods motion (except coupling rods), cylinders etc made quite a saving over building all new locomotives. And presumably with Aberdares and 28xx coming on line there was a surplus of small goods engines.