Does anyone know where I can find a replacement motor for a gscale 280?
There are 2 Spectrum 'g-scale' 2-8-0s. The older one is the outside frame version, and the newer one is the D&RGW C-19. This pic is the older one.
(http://estore.bachmanntrains.com/images/categories/LS_2-8-0.jpg)
Bachmann Parts is the usual place to find motors, etc. I did not see one listed for the older 2-8-0, but you could try a phone call to the Parts Dept.
The gears are the usual problem in the 2-8-0. Are you sure your problem is the motor? Can you hear it spinning when you apply power? If so, there is a new brass gear in the Parts store:
https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_142&products_id=10285 (https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_142&products_id=10285)