|Bettendorf bogie on a VG van|
In the parts section of their web site, they list a number of styles of bogies (or trucks as they call them). The most useful for WAGR modellers are the Bettendorf freight car trucks and, for some modern Westrail era wagons, the 50-ton roller bearing trucks.
|Bettendorf with "scale" wheels|
|50-ton roller bearing, with "scale" wheels|
Of course, the bogies are standard gauge so they have to be narrowed to suit Sn3½. The Bettendorf bogies are sprung so they can be easily be dismantled - but don't lose the springs. Kadee make an inexpensive manual uncoupling tool (#241), one end of which doubles as a "spring pic", which I have found useful for removing and inserting the springs.
The basic principle to narrow the bogies is to cut the centre from the original plastic bolster, and rejoin the two halves of the bolster. For a while, I was using K&S 6.35 mm brass channel to splice the two halves of the bolster back together. Recently, I went to the local hobby shop to get some more channel and they didn't have any, so I bought some K&S 6.35 mm x 3.2 mm rectangular brass tube instead and that actually worked better.
|Original bolster (bottom) and shortened bolster.|
The bolster is deeper towards the centre with a slope on both the top and bottom surfaces. I found that by grinding away the sloping parts with a Dremel motor tool and "plastic" cutting disk, the end pieces of the bolster are a snug fit in the rectangular brass tube. I found it easier to do the grinding with the original bolster in one piece, before cutting it into three pieces. Take care not to damage the "bumps" which locate the springs.
A length of between 18 and 18.5 mm seems to work well for the brass tube. This is based on fitting replacement wheelsets with 26 mm axles. The bearing holes in the sideframes are quite deep and I don't think 25 mm axles would work as the wheels would rub against the inside of the sideframes.
|Cut sections of original bolster with rectangular brass tube.|
I drill the centre pivot hole 2.2 mm as this will take a 2-56 screw with minimal slop. I drill the matching hole in the bottom of the brass tube a bit larger, say 2.5 mm, so that the bogie can rock a little bit from side to side or end to end. Obviously, it is important to get the pivot holes in the exact centre of the brass tube.
I have also drilled 2 small holes in the underside of the brass tube so that I can use small screws to secure the two halves of the bolster in place although, if they are a tight fit, this may not be necessary.
The bogies I have bought have been "rust brown" in colour so I have have airbrushed them (Revell 9 "Anthracite") before reassembling them. The current production are available in black, judging by the website photo, which would be better.
The 50-ton roller bearing bogies are not sprung, and are cast in one piece. I haven't actually used this type, but I have seen some that have been converted to Sn3½ (and there are no springs to lose).
Update - 23 January 2014
To simplify regauging of the Bettendorf bogies, I have designed a new bolster for 3D printing. The first test prints arrived today and they seem to have worked very well.
|Bettendorf bogies with 3D-printed bolsters (grey)|