GW Auto Trailers ..... almost more varieties than Heinz!

[John Candy]

 
9ft Equalised Bogie



The files to print this bogie are:
gauge3.info/downloads/american9block.stl (this is the main equalising block)
gauge3.info/downloads/american9frame.stl (this is the cosmetic outer frame)

Choice of axleboxes, which I have labelled "A" and "B"
The "A" type would appear to be the older of the two types.
Auto trailers with  "American" bogies appear with type "A" in older photos but some more recent photos show the "B" type (mainly in post-war and BR era photos).



gauge3.info/downloads/AmAbox.stl
gauge3.info/downloads/AmBbox.stl 

8ft Equalised Bogie



This bogie is visually similar to the 9ft type, the main identifying difference being the transverse leaf springs, of which there are just two (the 9ft bogie has three).
The 8ft version was rarely found under autotrailers (diagram "N" No.41 is an example) but commonly used under 57ft "Toplight" and other ordinary stock.
 
gauge3.info/downloads/american8block.stl (this is the main equalising block)
gauge3.info/downloads/american8frame.stl (this is the cosmetic outer frame)

Choice of axleboxes is as for 9ft bogie.

************************************************

The mounting ring (common to all my GWR bogies) :-
gauge3.info/downloads/bogieringmountA.stl

NEXT : More Auto trailer parts

[IanT]

Way beyond what I can do with SCAD John - lot's of effort here, well done.

Regards,

Ian

[John Candy]

Over past week I have been working on  the diagram "Z" autotrailer (construction is running in parallel with the "Q" and "U" 70ft trailers).

Diagram "Z"  was a flat-sided 59ft 6in trailer, matchboarded below the waist and  running on Dean 8ft 6in bogies.
"Z" was a conversion, carried out in 1915, from six steam railmotors, Nos. 3 to 8, the resulting trailers being re-numbered 99 to 104 and they lasted until the early 1950's. These were flat sided (no tumblehome) and when built,the first four ran on 8ft 6ins Dean bogies, the last two on 9ft "Fishbelly" bogies. The Dean bogies are covered in a previous post.

The intention is to 3D print large modules, leaving the minimal amount of assembly required. Each side will consist of three modules (necessary to fit the printer) and the first module is ready for a test print (which will take a very long time). Each side is a mirror image of the other, so the three modules will (with addition of a "mirror" instruction) print both sides. The ends will also be in three parts and both ends (driving and luggage) are basically identical, differing in just a few extra add-on fittings such as "gong", alarm gear, etc.

I was concerned as to whether the matchboarding would be sufficiently well-defined but a quick test print of a small section was very satisfactory.

Although the "Z" is subject of this project, the modular source files can be quickly adapted to suit other matchboard trailers by rearranging the panelling, windows and door spacings.

You don't need an " auto tank" (commonly employed were specially fitted 0-4-2 tanks of classes 517 or 48XX/14XX, 2-4-0 "Metro Tanks", some Pannier Tanks and , in BR days, a few small Prairie tanks) since auto trailers were often hauled as normal stock by Panniers, Dean Goods, 2251 class,  small Prairie tanks and other non-auto fitted locos.

The STL files will be made available once the test prints have been verified.

P.S. Could this be the time for you to drop hints about a 3d printer for Christmas?!



 

[cabbage]

There does seem to be a "filament famine" at the moment in my area.
This does happen every now and again.

I do remember someone asking at a G3S committee meeting - "Well why would anybody need one?"

🤣

Regards

Ralph

[MikeWilliams]

John, Wikipedia tells me that the GWR had 256 Auto Trailers.  With all the varied parts you are making I just wonder what proportion of the stock you are modelling - all of them? 

Mike

[John Candy]

It took a while for the "Z" files to reach the head of the queue but one side of the autotrailer is now printed.

It is in four parts, necessary owing to the print bed limit of 350mm and desire to align the joints with the door edges. Printed at 160 microns it took 25 hours (the printer can go down to 50 microns....God knows how long that would have taken) .

The second side is now printing and the files for the ends (both to the same pattern) are in preparation.
Being in black PLA, they are not easy to photograph (particularly  under artificial light) but the photos show the parts as removed from the print bed and before any fettling/tidying.

The fourth of rhe quintet of autotrailers being produced will be to diagram A9, which had a particularly unusual window design, unique among autotrailers. When the "Q", "U", "Z" and "A9" have been completed, I will (with the A10 GRS kit version) have five GWR autotrailers....that will  be more than enough for now (especially since I have only one auto tank, No. 4817 ). Hopefully, I shall get around at some stage, to producing a 64XX Pannier auto tank to handle a four car (2+64XX+2) set.

[753]

John

Your auto coach build is looking very good, I am following with interest.

Mike

[John Candy]

When you unwrap your shiny, new, 3D printer on Christmas Day and are wondering what to print ...... here is the perfect solution to "break it in".

The ten (STL) files contained in this ZIP file will produce the sides and ends for the diagram "Z" trailer (as in the photo).


http://gauge3.info/downloads/Z.zip

For a single trailer, you will require:-
One each of the "side specific" parts plus
two each of the common, to both sides/ends, parts.

The instructions (and additional STL files) to complete the model will follow over the next few weeks.
__________________________________________________
Information and suggestions for those new to 3D printing.

1) Power supply : Some of these files take 12 hours or more to print and a stable power supply will ensure they are not damaged by power "blips"/low voltage or short outages (ever more likely if the doom-mongers are correct). I use a PowerWalker VI 2200 1200W UPS, which should run my printer for around 45 minutes without mains power. https://www.amazon.co.uk/PowerWalker-2200-LCD-IEC-1200W/dp/B00O636RRC

2) Filament : I have used black PLA from Amazon (branded "Eono") to print my autotrailer parts. As guide to quantity required, I printed all the parts shown in the photo below from a 1kg drum and still have plenty to spare (in fact, almost enough to print a second set).



https://www.amazon.co.uk/Amazon-Brand-Filament-1-75mm-Printer/dp/B09H6N9R58

3) Cost : The parts shown used approx. 530 grammes of  PLA (costing around 11 GBP) and an educated guess as to the amount of power consumed would be around 8 kWh (units).

[John Candy]

My second matchboarded trailer is diagram A9, selected for its unique pattern of windows which includes triple-paned units, consisting of a droplight flanked by narrow fixed lights.

As with the "Z", each side will consist of four components and the ends are same as for the "Z".

The first side section is ready for printing and these renderings of the OpenSCAD file illustrate the pattern.

 

 

[John Candy]

Diagram A9

http://gauge3.info/downloads/A9.zip

The twelve (STL) files contained in this ZIP file will produce the sides and ends for the diagram "A9" trailer.
Each side consists of 5 files (4 are specific to each side but the fifth, the central door, is common to both sides).
The 3 parts for the ends are the same for both the driving and luggage ends.

Internal Partitions for "A9" and "Z" autotrailers.

N.B. The previously uploaded internal partitions for the "Q" and "U" trailers ARE NOT interchangeable with these .... the roof profile is different.

This ZIP download http://gauge3.info/downloads/A9_Z_partitions.zip
contains three STL files common to both the A9 and Z trailers (in fact are suitable for any GWR matchboarded trailer). These files will print the internal divisions separating the passenger saloons from the driving compartment, luggage compartment and central entrance vestibule.

To produce the four divisions required you will need (ordered from the leading/driving end):
a) 1 x "driving" + 1 x double "passenger" door (glued back-to-back, dividing driver from passenger saloon).
b) 2 x single door partitions (the item labelled "luggage" partition....glued back-to-back, dividing passenger saloon from entrance).
c) 2 x double "passenger" door partitions  (glued back-to-back dividing vestibule from second passenger saloon).
d) 2 x single door  "luggage"(glued back-to-back dividing luggage from passenger saloon)

Seating
This ZIP download http://gauge3.info/downloads/A9_Z_seats.zip
contains three STL files to print the transverse seating : There is a seat with LH arm rest, a seat with RH arm rest and a back-to-back pair.
For an  A9 or Z  you will require two prints from each file (total of 6 units). The remainder of the seating was longitudinal and the files have previously been produced for the "Q" and "U" trailers (details specific to the A9 and Z will be provided when the assembly instructions are produced).

[John Candy]

In connection with the auto trailer projects, I shall be having the appropriate buffers cast in brass and nickel-silver (guides in brass; heads/shafts in n/s). These buffers fit all the diagrams except A6 (which had flat ends).

The 3D-printed patterns being used are produced from the OpenSCAD files shown below.

I shall be placing an order for 24 buffers (i.e. sets for 6 trailers) but if anyone here is building a trailer (or two) then I am willing to increase the quantity and supply "at cost" (firm orders only....I don't want to be left with surplus stock).

Regards,
John.

[John Candy]

Last Orders!

As matters stand, I shall be placing an order of 40 buffers (i.e. enough for ten coaches) and all are spoken for.
If you want a set, then now is the time to place your order.
I don't yet have a price but they will be passed to you "at cost".
The guides will be cast in brass and the heads/shafts in nickel silver.
Regards,
John.

[John Candy]

Today I received from Mike Williams the first of the cast autotrailer buffers.
The guides are brass and the heads nickel silver.
The attached photos are as they arrived (I have not removed casting sprue nor cleaned in any way).

I have arranged with Mike that he will add to his stocklist and supply to anyone requiring them.
So please contact Williams Models if you require sets.

Regards,
John

[John Candy]

I started the autotrailer project more than 3 years ago but it got pushed back in favour of other rolling stock projects, as you will have seen from my forum posts.

Today, the first two trailers have been completed (apart from some minor paint touching-up and application the transfers, which I shall be printing tomorrow) .
They are both "matchboard" types converted from steam railmotors.
Diagram "Z" is the earlier of the two, having been converted in 1915, while the A9 diagram trailers were converted 1919/20.

Both these are to be available as kits from Ant Terranova (New Land 3D) and he is working hard to assemble display models for the AGM (unfortunately, I shall not be there).

I am aware that the "U" diagram trailer (one of my four autotrailer projects launched at the same time) has generated enquiries and it is at the top of my list for early completion. 

I am mulling over the possibility of a steam railmotor (battery powered) but the complication of the power bogie (with Walschaerts valve gear) is making me wonder whether it is worth the effort and whether a kit would sell. 

All my rolling stock designs have been made available to Ant for kit production and he is making good progress, introducing as many as he can, as quickly as possible.
Ant has also taken on my buildings and accessories range (formerly marketed under the Thatchworks brand by Mark Thatcher) so he has "a lot on his plate"!

Please, watch out at the AGM for Ant's stand and  support his work.

The end of the Gauge 3 coach famine is nigh!

John.

P.S. Ant is also offering the full range of my "Monobloc" bogies, so these can be bought separately for your own rolling stock projects.




Above : Diagram "A9"
Below : Diagram "Z"




Below : Close-up details of both types

[IanT]

Well my first thought was just "WoW" John.

Lovely models & great detailing.

Regards,


IanT