Grant,
It should be possible to install insulated scale wheels on the Lionel axles and then insulate the trucks from the frame or install pickup wipers to allow the models to operate on 2 rail. Kadee couplers can be attached with adapters made to fit the specific model. Pilots can usually be attached to the frame. I have converted more three rail engines to 2 rail than I care to count. However, being primarily a steam/first generation modeler, I don't even know what a Sd90c looks like. There is at least one modern model produced by Lionel or MTH that has such beautiful detail on the trucks (brake rigging and piping) that they will not swing clear of the pilot steps once the pilots are attached to the engine frame instead of to the trucks. The choice or converting this was to either remove the detail on the front end of each truck or leave the pilots on the trucks. Customer opted to have the pilots left on the trucks.
NWSL sells wheels that can be modified and insulated to fit the Lionel axles. You will need a decent lathe or a friend with one to modify the wheels to fit the Lionel axles.
As someone above said, the electronics have a good value so if you remove them be careful with the components and do not cut any more wires than you have to.
Best regards,
Joe Foehrkolb
