Tuesday, 17 November 2015

BHP Iron Ore Cars HO Scale

Marbelup Models has developed HO scale 3D-printed models of 4 different types of ore cars as used by BHP Iron Ore in the Pilbara region of Western Australia.

The 4 versions are:

  • "Comeng" - built 1969-1982
  • "Goninans tapered floor" - built 1997-1998
  • "Goninans flat floor" - built 1999-2000
  • "Golynx" - built 2001-2003 approx.
The Comeng ore cars are very similar to the original Oroville cars imported from the US at the start of the Mt Newman Mining operation in the 1960's.  For more information and photos of the prototype wagons, see the Pilbara Railways web site.

"Comeng" ore car (computer rendering)

"Goninans tapered floor" ore car (computer rendering)
All of the ore cars are supplied as "body only", the only other parts included are Kadee #262 coupler boxes.  The modeller must supply and fit bogies and couplers, as well as detail items such as brake wheel, air hoses, handrails, etc.  The level of detail is optional, to some extent, depending on the modeller's preferences.

The models accept Kadee #148 or #158 whisker couplers.  These are available from Hobby shops in bulk packs of couplers only, in addition to the usual packs of 2-pairs of couplers with boxes.

As an option, the models will also accept Glatzl rotary couplers (at one end) which are available from the US through Sergent Engineering.  Sergent also sell matching dummy couplers which work well with the Glatzl rotary couplers.  Both the Glatzl rotary and dummy couplers will mate with Kadee "scale head" couplers but will not couple or uncouple automatically.  A simple modification is required to the Glatzl rotary couplers prior to installation, as they intended to directly fit onto a specific US coal car which has different dimensions to the BHP ore cars.

Left: "Goninans flat floor" in Polyamide material. Right: "Golynx" car in Prime Grey material. (Click on any photo to see enlarged version.)
The BHP ore cars are available in two different 3D-printed materials: Polyamide and Prime Gray.  The Polyamide material is about half the price of Prime Gray and has a slightly rough surface texture.  Costs for the ore cars are as follows:
  • Polyamide material: $25 each for minimum quantity of 5.
  • Prime Gray material: $55 each, no minimum quantity
  • Prime Gray material: $50 each, minimum quantity of 5.
All price are subject to change depending on variations on the exchange rate with the Euro.

Refer to the "How to Order" page for information on ordering and postage (if required).  These models require a 50% deposit at time of ordering.

Sunday, 15 November 2015

What's In the Works

This page provides a sneak preview of projects currently in development or being contemplated.

Feel free to email Marbelup Models if you are interested in any of these models and would like to be kept informed of progress.  Your feedback and interest may well influence priorities for design of future models.  Also feel free to nominate ideas for possible future models.

WAGR Clerestory Roof Z Van (also Commonwealth Railways NY and NYA)

These guards vans date from the late 1890's and there were versions with platforms at one ends or both ends.  Some lasted into the 1970's in departmental service so, even in the diesel era, it would not be out of place to have one parked on a siding or as part of a work train.

Quite a few were transferred to Commonwealth Railways during WWII.  New Zealand railways had some very similar vans (single ended) which have been previously available in brass.  Correct bogies are available for the Sn3½ version from North Yard in New Zealand.

Project Status: Test models have arrived in 4 mm scale.  Design for double-ended version is almost complete in Sn3½.  Could be produced for HOn3½ (or even HOn3) if their is demand.

WAGR/Westrail XW Grain Hopper

The XW (and later variations) were the most numerous grain hoppers on the WAGR/Westrail narrow gauge lines and were introduced in 1972.

The model can be potentially produced in both Sn3½ and HOn3½ scale (or HO if you don't mind the gauge difference!)

Project Status: Information gathered.  3D drawing commenced for basic body shape.  Lots of details to be added.  Research commenced re custom-etched roofwalks and ladders.

WAGR QU Flat Wagon

The QU's were the first "modern" flat wagon on the narrow gauge, dating from 1963.  Unusually, they were painted black initially and then yellow.

The model can be potentially produced in both Sn3½ and HOn3½ scale.

Project Status: Photos and measurements taken of stored wagons at Pemberton.  3D design not started.

WAGR/Westrail WFX Flat Wagon

Project Status: A few people interested in HO model.  Not started yet.

Friday, 13 November 2015

WW Assembly Tips

Parts List

  • Bogies: e.g. "100-ton roller bearing" by Kadee part no 569 or 1569 (see below) or Tichy #3009 (1 pair) or #3036 (10 pairs)
  • Couplers: Kadee #148 or #158 (see below)
  • Replacement Metal Wheelsets 36" diameter - if using Tichy bogies, e.g. Intermountain #40051 (4 per wagon).
  • Coupler boxes: Kadee #262 (supplied)
  • Air Brake Hoses, e.g. Detail Associates #6206
  • Brass wire: 0.4 mm for handrails, etc.
  • Fixing screws: 2 x 2-56 x 8 mm (5/16") metal, 2 x 2-56 x 12 mm (1/2") nylon - (see below)
  • Glue, paint, decals
Marbelup Models can supply "Parts Kit" containing all of the above items, with the exception of glue, paint and decals, with a choice of Kadee or Tichy bogies.

Removing Support Structures

Carefully remove the support structure from the wagon.  It is suggested to use a sharp knife to cut the supports away from visible areas.  Take particular care around the roofwalk supports at the ends of the wagon, and the discharge hatches at the bottom of the wagon.  There should be a row of supports along each side of the wagon, under the side sills.  Once these are removed, the supports under the discharge hatches will be visible.

Typical Support Structure prior to removal.
Once the majority of the support structure has been removed, carefully go over the wagon and cut away the small supports which typically extend from one part to another including, for example, inside the coupler housing.  An Exacto type hobby knife with a sharp pointed blade (Exacto #11 or similar) is quite useful for getting into the nooks and crannies.  

Go over the model and smooth off any remnants of the fine supports, expecially in the visible areas.  A sanding stick or small file can be useful for this.

Bogie and Coupler Mounting Holes

The mounting holes for the couplers and bogies have been printed at 1.8 mm diameter to suit 2-56 screws.  

Due to the difficulty of tapping the blind holes for the bogies, the 3D print includes vertical grooves in the sides of the holes to help the screws cut their own threads, so tapping the holes is not required nor recommended.

Note: An economical source of steel 2-56 screws in various lengths is Little Bird Electronics.  


The suggested bogies are Kadee #569 or #1569, the only difference being the width of the wheels.  Atlas and Athearn and others make similar bogies, but the advantage of the Kadee ones is that they add some weight to the wagon due to the use of a relatively heavy plastic material.

Tichy Train Group also makes an economical 1-piece plastic bogie #3009 (1 pair) or #3036 (10 pairs), however these are supplied with relatively low quality plastic wheelsets which are also too small in diameter (33").  Intermountain Railway Company sell high quality all-brass wheelsets which fit well in the Tichy bogies and are the correct size, i.e. 36".

Note that Intermountain do also sell complete roller bearing bogies but these are supplied with 33" wheelsets only.  Be wary of other brands of bogies as well.  In general, US roller bearing bogie (trucks) described as "100-ton" have 36" wheelsets and "70-ton" have 33" wheelsets.

Note that the depth of the blind holes for the bogies is 4 mm.  If using Kadee bogies, the supplied screws will need trimming to a length of 7.5 - 8 mm to avoid damaging the wagon (or shorter screws substituted).  Do not drill the bogie mounting holes any deeper, as they are directly under the ends of the hopper and the drilled hole will "break through" and be visible on the finished model.


The WW is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.

The draft gear boxes supplied with the couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes, which are available separately, are narrower and have been used because they allow details such as the brake hoses to be positioned the scale distance from the wagon centre line.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Because of the deep end sill on the WW series of wagons, the model has been designed so the coupler and draft gear box slides into a recess via a hole in the end sill.  Make sure that any remnants of support structure from the 3D printing process have been cleaned up from inside the coupler mounting recess.

The draft gear box will probably be a snug fit inside the mounting recess.  A hole has been provided for a 2-56 fixing screw to prevent the coupler from being pulled out.  Note that the maximum length of the screw is 4.25 mm, so it is likely the screw will have to be cut to length.  Provided a metal screw is first used to create a thread in the provided hole, a nylon screw (e.g. Kadee #256) can be used for the permanent fixing.  A nylon screw is much easier to cut to the desired length, and the Kadee nylon screws have a low profile head which provides maximum clearance for the outboard axles.

Kadee nylon 2-56 screws are available from good hobby shops.

Note that the height from rail level to the top of coupler mounting surface should be 11.5 mm, the standard for Kadee couplers.

Brake Rods

There are 3 brakes rods which can be formed from 0.4 mm brass wire: one long one which runs along the side of the wagon and 2 short ones, which disappear into holes provided in the ends of the hopper.

Brake Rods - 2 out of 3 shown.
Typically, the holes for the brake rods are printed at 0.4 mm diameter but all will require cleaning out using a pin vice and drill bit, e.g. 0.45 mm.

Note that cleaning out the hole in the longer of the two brake levers is a bit tricky, due to its location under the sloping end of the hopper.  This hole has been printed at 0.6 mm but will probably still need cleaning out.  One option is to use a length of 0.4 mm brass wire, approx. 75 mm long, held in a pin vice as a crude drill, by cutting one end at approx. 45 degrees to form cutting surfaces.  This long "drill" can then be poked through the gaps in the supports for the roofwalk (prior to fitting the roofwalk, of course) to reach the hole in the brake lever.  Another, perhaps better, alternative is to use a purpose-made cutting broach, such as the ones available from DCC Concepts.  These have a long, tapered cutting blade which can be used for enlarging small holes.  The second smallest broach in the DCC Concepts set is a suitable size for this application, as the diameter near the tip is just over 0.4 mm.
Cutting Broaches

The holes for the long brake rod, which links the two brake levers, theoretically, measure 137.4 mm centre-to-centre.  This brake rod should have a 90-degree bend at each end, approx 1 mm long to fit in the holes.  Because of variations in the 3D-printing process, the actual length required may vary slightly, so some fitting will be required.  When the brake rod fits between in the holes at each end, it should be secured in place with superglue and also glued to the 5 support brackets along the side of the wagon.

The two short brake rods should each be approx. 12 mm long, with a 90-degree bend at one end, approx. 1 mm long.  The straight end fits in the hole provided in the end of the hopper and the bent into fits into the corresponding brake lever.


The WW has an inverted U-shaped handrail at the end near the handbrake, and a pair of vertical handrails at the opposite end.  In addition, the AGWY/AGSY has 2 more pairs of vertical handrails at other corners.  Small starter holes have been provided to locate handrails, which should be drilled out, e.g. with a 0.45 mm drill bit in a pin vice.

The handrails can be formed from 0.4 mm brass wire.  The U-shaped handrail is 6 mm wide (centre to centre) and 8.5 mm high, which allows for 1 mm to be inserted into the holes.  The vertical handrails are also 8.5 mm high.

Door Operating Mechanism Rods (optional)

As an optional detail item, small holes have been provided for three rods which form part of the door operating mechanism on the real WW's.  The holes should be cleaned out with a 0.45 mm drill bit, after which the rods can be cut from 0.4 mm brass wire and glued into position.

From left to right, as picture below, the lengths of the rods are approx. 14.5, 15, and 13.5 mm.

Air Brake Hoses

Small brackets are provided next to the couplers on each end of the wagon for air brake hoses.  Cast plastic hoses are available from Detail Associates, part number 6206.  Carefully drill out the starter hole provided in the supporting bracket to suit the diameter of the "pipe" on the air hose.  A suggested drill size is 0.65 mm.

Uncoupling Levers

A small starter hole has been provided underneath the coupler, as well as a notched bracket towards the left side of the wagon, when view from the end.  The uncoupling lever can be shaped from 0.4 mm brass wire, with a 90 degree bend for attachment into the central fixing hole.   The diagram below shows the approximate shape to aim for, but feel free to adjust the measurements to suit your model.

After positioning each uncoupling lever, check that the coupler can swing freely and is not obstructed, prior to gluing it into position.

Filling Discharge Door Openings (optional)

If desired, the rectangular holes in the bottom discharge doors can be filled with pieces of styrene sheet.  Suggested dimensions are 5 mm x 9 mm x 0.5 mm thick.  Small ledges have been provided inside the openings for this purpose.

It was necessary to leave these holes open for the 3D-printing process (stereolithography) to allow the unused liquid plastic resin to drain from the interior of the hopper.

Etched Brass Parts

The supplied etched parts consist of:
  • roofwalk and ladder assembly
  • brake wheel
  • small steps (x3)
  • large step
For all of the etched parts, the first step is to cut them free from the "fret", e.g. using a knife.  The small attachment points are etched half way through to make cutting easier. Note that this will dull the knife blade, so don't use a new blade (or use a "snap-off" blade and discard the dulled blade.

Using a small file, remove any roughness at the attachment points and clean up any other areas requiring attention.  Sometimes, due to variations in the etching over the entire sheet, small sections of very thin brass can remain but these are easy to clean up.

Roofwalk and Ladders (WW only, not AGWY/AGSY)

The roofwalk has attached ladders which need to the folder "down" and handrails (both loop and straight) which need to he folder "up".  Note that the etch is symmetrical so it doesn't matter which is up or down to start with.

While there are special tools available for precisely folding etched brass models, a pair of pliers with smooth jaws or a small vice will do a pretty good job.

Completed folding, using a small vice.

If using a vice, for example, the sequence of folding is as follows:
  1. Clamp the roofwalk with the ladder pointing up and the etch of the roofwalk level with the top of the jaws.  For this step, the ladder can be roughly in the centre of the vice.
  2. Using an object with hard surface and sharp, square corners (such as the handle of a small "engineers" square), fold the ladder away from you.  Take care to NOT fold the straight handrail at the same time, and try to get a nice, sharp fold.  Fold to an angle of about 80 degrees, not the full 90 degrees.
  3. Fold the straight handrail towards you, this time to 90 degrees.
  4. Reposition the roofwalk in the vice so that the end of the main section of the roofwalk is level with the end of the vice jaws.
  5. Fold the loop handrail towards you, to 90 degrees.
  6. Repeat for the other end, taking care to match the directions of folding.
Once folded, test fit the roofwalk in position on top of the wagon.  Small, spring tweezers (e.g. Kadee #1020) are useful for lightly clamping it in position at each end.  The ends of the ladders should fit into small notched provided in the side sills of the wagon.  The ends of the ladder may be a fraction of a millimetre too long.  If this is the case, trim the ends using sharp sidecutters or similar tool.  (A Xuron track cutter is ideal.)

Adjust the fold angle of the ladders slightly, if necessary, to ensure the roofwalk sits level on the supports at the end of the wagon while the bottom of the ladders fits into the notches in the side sill.

When satisfied with the fit, glue the ladder in position with superglue.  However,  You may want to consider gluing the roofwalk on only after all other assembly work has been completed as the wagon needs to be handled with care once the roofwalk is fitted, to avoid damaging the handrails on top.

Steps (Same for WW and AGWY/AGSY)

The single, larger step should be fitted to the corner of the wagon nearest the handrake.  The bottom end of the step has a half-etched fold line, and the top of the step should be folded in the opposite direction.  

The three, smaller steps should be fitted in the remaining corners of the wagon.  They require a single 90-degree fold at the top of each step.

Note the step locations and orientation, as per the diagrams below.  Glue the steps to the underside of the wagon with superglue.

Step Locations - Handbrake End

Step Locations - Handbrake End (bottom view)

Handbrake Wheel

A 0.5 mm spigot has been provided on the handbrake assembly, to which the wheel can be glued.  If necessary, open out the central hole in the handbrake wheel with a 0.6 or 0.7 mm drill bit to fit over the spigot.


Compartments have been provided at each end of the WW for gluing lead shot or small pieces of sheet lead to add extra weight.  Non-lead based alternatives are also available including "Liquid Gravity".

With the suggested Kadee bogies, the completed WW weighs approx. 60 grams.  For this length wagon, the NMRA recommended weight is 110 grams, although some modellers feel that the NMRA weight recommendations are excessive.  A total weight of somewhere between 90 and 100 grams is probably about right.

Weight Compartments (arrowed)


Either enamel or acrylic hobby paints can be used to paint the finished model.  The model pictured has been painted with Testors Model Master Enamel colour "Gelb RLM 04".  (Gelb is German for yellow!)

WW Wheat Wagon (Standard Gauge, HO Scale)

Photo of test model.
The WAGR/Westrail WW standard gauge wheat wagon entered service in 1966 and formed the mainstay of the standard gauge grain fleet for over 45 years until Cooperative Bulk Handling introduced their own locomotives and rollingstock in 2012.  They were affectionately known as "Willie Weeties".  

The Marbelup Models WW consists of a 1-piece 3D-printed body and an etched brass roofwalk which incorporate the ladders and handrails as a "fold-up" assembly (no soldering required).  Additional etched brass parts are also included for the corner steps and brake wheel.

WW with L class (loco by Haskell Models)
For prototype information, please refer to the WA Wagon Pages.

The later version with air-operated roof hatch and no roofwalks, i.e. the AGWY and AGSY, is also available.  The difference between the prototype AGWY and AGSY relates to improved seals on the discharge hatches (AGSY) to allow use with canola, which is finer than other grains.  The model can represent either version.  Some WW's also had the improved seals fitted and were coded WWS.

The AGWY/AGSY has an extra air cylinder on the end opposite the brake wheel, in connection with the air-operated roof hatch.
Side of AGWY/AGSY showing runner for air-operated roof hatch.
Opposite side of AGWY/AGSY.
Detail on brake wheel end of AGWY/AGSY.
Both the WW and AGWY/AGSY are available to order now. 

Expected selling prices for the body-only "kit" (including etched parts and Kadee #262 coupler boxes) are $80 for WW and $80 for AGWY plus postage if required.  (Prices are subject to variation due to changes in the Euro exchange rate.)

The purchaser must separately obtain parts to complete the model including bogies, couplers, brass wire, paint and decals.  Suitable bogies are available from Kadee (#569 or #1569).  Detailed instructions including list of parts required are now available online.  

Marbelup Models has ordered some suitable bogies and these will be available, together with couplers, air hoses, brass wire and fixing screws, as a "parts kit", containing all the extra parts necessary to produce a running model.  Quantities are limited.  Glue, paint and decals not included.  Two types of "parts kit" will be available:

"Premium Parts Kit" including Kadee #569 bogies, and parts as listed above: $25 per wagon.
"Quality Parts Kit" including Tichy #3009 bogies, Intermountain metal wheelsets, and parts listed above: $15 per wagon.

The Kadee bogies are from HGC plastic, and are a 2-piece design which provides compensation over uneven track.  They are are also self-centering, an aid to placing wagons on the track.  Kadee wheelsets have black metal wheels on a plastic (Delrin) axles.

The Tichy bogies are 1-piece moulded in plastic.  Intermountain wheelsets have brass wheels and axles, with a weathered finish.