Hey doc, The c-19 Chassis is available in the parts store. It is complete with the motor and gearbox. The motor an gearbox do not seem to be available as a separate item.
Here is a link:
https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_580&products_id=5163
Loco Bill
Here is a link:
https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_580&products_id=5163
Loco Bill