So here are some photos of a CP 50' High Cube I just converted this evening. High level steps I performed are as follows
- remove the 4 screws which hold the two door guides on
- remove the 2 door guides and the 2 doors
- set the door guides, doors and 4 screws a side
- remove the 4 screws (2 at each end) which hold the underframe to the body
- set aside the screws and the body
- remove the 2 screws which hold the MTH 3R trucks on the underframe.
- set aside the 3R trucks and screws
- Install Atlas 100T roller bearing trucks using the provided bolster and screws
- tap the 4 holes to mount the kadee gearbox using a 2-56 tap
- Assemble the Kadee gearbox, coupler, spring
- Install one MicroMark O scale Kadee Shim on the top plate of the Kadee gearbox
- Use 4 2-56 3/8" long screws to attach the assembled Kadee couplers on each end
- reassemble the car