After a couple of years I finally got round to model a rake of nine National Power JMA's from Bachmann Freightliner HHA's. I used the information on Lyneux's blog of his go at the JMA: http://www.rmweb.co.uk/community/index.php?/blog/864/entry-11917-national-power-jma-part-2-bashing-the-Bachmann-hha/
The first job - bodies
I then removed the side detail on the hopper sides and at one end on one side I cut a hole in the side for the access to the brake distributer and isolation cock. I then and glued 0.3mm brass wire around the edge for the lip.
I then soaked the sides in surgical spirit for 30 minutes to remove the Bachmann paint. After 30 minutes I used a tooth brush to remove the paint, washed the bodies with warm soapy water and left them to dry. After they had dried, I glued a thin piece of 3mm x 1mm plastic to the side of one end of the body and filed it down so that it was level.
As the HHA end is incorrect for the JMA, I purchased Evergreen Scale Models sheet styrene 2mm spacing metal siding. I traced around an end of the HHA and then cut out a new end from the styrene sheet, then cut off the last 'rib'.
The wheels were purchased from Colin Craig and the 3D printed bogies purchased from Lyneux's Shapeways shop: https://www.shapeways.com/product/68BXCJK2W/ltf25-np-v0-6-2-pairs-4-bogies-oo-scale
First I cleaned the bogies in warm soapy water and left them to dry. I then cut off the spares and made the suspension from sequins and 8mm rubber O rings. I glued the made up suspension onto the bogies and sprayed them with white primer.
The rake will consist of seven inners and two outers. For the inners I cut off the draw hooks and buffers and for the two outers I left the drawhook and buffers in place. On the ends, at each end, I drilled five small holes to replicate the buffer mount holes on the wagons, and cut out part of the end beam for the kadee coupling
take apart again
rub down and spray blue
put wagon back together, mask off blue and spray grey
buckeye pull wire and mount end detail
small paint details such as hopper door open levers etc.