These N-gauge/2mmFS model 6ft wheelbase plateback bogies are designed to fit the ICI hopper wagon
which is sold on Shapeways by Chapel Design. They would also be suitable for the very similar Summers
hopper wagon, but you would have to remove the raised ICI lettering from the Chapel Design model.
There is a good book by Paul Harrison which goes into the detail differences between these wagons and the
bogies used with them at various times.
As with my other 3D print bogies, you can use the fixed rapido style couplers or the NEM pockets - just cut
off whichever ones you don't want.
With the bogies, I have included a stack of 12 brake handwheel discs which may come in useful on the wagon solebar (you only need 2, so there are plenty of spares to practice on). There is a central hole through the discs for 0.25mm brass wire if you want to mount them more securely than just glue or sticky paint, and two slots in the outside edge of the discs for 0.25 mm wire to make the forward-projecting handles. If this all sounds like too much bother then leave them in the packet, they won't have added much to the price.
UPDATE 2017-10-08 I'm happy to offer these for sale now. To fit Parkside Dundas 6.2mm diameter wheels on 14.8mm axles to these bogies, and use them as intended on the ICI hopper wagon, you will need to file or scrape away some of the bottom edge of the angled struts on the wagon chassis. There are eight of them altogether, radiating from the tops of the bogie bosses and you need to make clearance for the wheel flanges and let the bogies turn. This would be less of a problem with 2mmFS wheels, I expect. I suggest you do this before you remove the hopper support stays from the wagon. If you don't fancy this, you could shim the body up on the bogies with 0.5mm or so washers, but this will spoil the ride height in my opinion. You could instead use Parkside Dundas 5mm wheels, but the batch of these I bought most recently have nasty gold coloured tyres and seemingly 15.2mm axles like Graham Farish wheels. These would need a little more material than usual to be drilled out inside the axleboxes to avoid over-straining the bogie sideplates. Finally, and only if necessary, open out the bogie mounting holes a little with a rat-tail file to give a close but free fit on the wagon chassis.
Close observers may know that these bogies carried at least two designs of axlebox in service. On this model I have opted for the "box-front-cover-plate-has-fallen-off" look, which could either be filled to give a cleaner front, or filed a little from the bottom to look more like roller-bearings. If you strongly prefer a particular design and would like several pairs, let me know and I will consider making a set to your specification.
I haven't tried fitting the brake handwheels to the wagon solebars yet.