Purchase P87 Athearn Type half axle wheels from P87stores (http://www.proto87.com/) or NWSL (http://www.nwsl.com/) - T Class 40" and Y Class 42".
Step 1. Make spacers in the lathe, so wheels stay in their the bogie housing correctly (about 1.3mm length).
Step 2. Remove about 0.7mm off each half axle, so you do not have to drill holes to bogie sideframes for axles.
Step 3. Move wheels out on the axle by 0.9mm
Step 4. Assemble wheels with back to back gauge (bottom left on image below). Put a few drops of loctite 609 on the gear when assembling, ensuring there is no loctite near the square phospher bronze housing mounts. The square phospher bronze housing mounts must be able to freely turn. Allow loctite to set.