For those that have an extra 736 lying around, a relatively quick and easy conversion of a Lionel Berkshire to a Northern without too much hacking and slashing (the other more involved method requires rebuilding the steam chest casting).
The steam chest is removed and hogged out to make room for the rear wheels of the pilot truck. The wheel base of a Hudson truck is shortened (front axel moved back about 1/8 to 3/16 inch) and then mounted to the frame. I made a new truck retaining plate to get the proper size to retain the truck and allow a hole for the shell mounting screw. It will probably require some trial and error fitting until all the necessary clearances are met.
This will give you a Northern to run with your Berks without too much trouble and cheaper than a 746.
