Monday, 15 September 2014

RB Open Wagon Construction Tips

Removal of Support Structure

In general, it is best to first cut away the supports from the areas which have small details, and the areas which will be visible on the the finished model with a sharp hobby knife.  (An X-Acto style knife with a #11 fine blade can be useful for the fiddly bits.) Take particular care removing the supports from the brake handles, queen posts, door bumper strips, vacuum hoses and underfloor brake gear.

The brake handles have "sacrificial" guards around them to provide some protection against breakage during production and shipping of the 3D printed model.  It is suggested to leave these in place until most of the other work has been done to minimise the risk of breakage to these delicate parts.

Once the supports have been cut away from the delicate areas, the remaining supports can be broken away by wiggling them or applying pressure to break the small attachment points.

Non-Tapping Holes

The holes for the couplers and bogies are designed to accommodate 2-56 or 8BA screws without tapping.  This also has the advantage that the screws remain tight, so they won't accidentally work loose (especially for the bogies).

Note:  Tapping the holes is not recommended as it will remove more material and potentially lead to stripped threads.


Railwest Models sells suitable arch-bar bogies.

If necessary, adjust the height of the wagon on the bogies so that the coupler mounting surface is 11.5 mm above rail level.


The VG 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 #148 and #158 couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes 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.

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


Handrails can be formed from 0.4 mm brass wire.  Starter holes are provided on the ends, which should be opened out with a 0.45 mm or 0.5 mm drill bit.

The lengths of the end handrails (centre to centre) is 4.5 mm.  Once in position, the handrails and other brass details can be secured with Super Glue.

Truss Rods

The RB has four truss rods which can be formed from 0.6 mm brass wire.  The diagram below gives the dimensions for bending the truss rods.  The longer truss rods are on the outside of the wagon.

The anchor points on the underframe for the ends of the truss rods have preformed holes which should be drilled out with a 0.65 or 0.7 mm drill bit.

Brake Rods

There are a total of 5 brake rods which can be formed from 0.4 mm brass wire.  Starter holes are provided which should be opened out with a 0.45 mm or 0.5 mm drill bit.

Two long brake rods go from the handbrake lever at each end to the main brake shaft near the centre of the wagon.  Because the main brake shaft is offset slightly from the wagon centre line, the length of these rods is 63 mm and 58.6 mm, not including a right angle bend of approx. 1 mm at each end.  The bogie bolsters include holes though which these long brake rods can be threaded.

The other three brake rods are near the wagon centre line and represent the rods which, in real life, connect to the brake rigging on the bogies.  At the left end, as pictured above, the brake rod should be 49.5 mm long, not including a right angle bend of approx. 1 mm at one end only.  The other end attaches to a hole near the bogie pivot point.

At the right end, there are two rods which are connected via an intermediate lever.  The first is 29.2 mm long not including right angle bends of approx. 1 mm at each end.  The second rod is 26 mm long with a right angle bend at one end only, the other end attaching to a hole near the bogie pivot point.