These are intended to be used for Freight Wagons.  They are not designed to be used for Passenger Haulage.  They come with 4 side frames and 2 bolsters for $165.00.  No axles, wheels, or bearings are provided.  They can be used with In Line Roller Skate Bearings (22 O.D. x 8mm I.D. x 7mm Wide).  We sell these for $15.00 a set of 4.  The axles needed are 16mm and the bogies can be sprung (springs are not supplied, but the details of the springs can be provided.  The bolsters contain 2 6mm stainless steel rods.