Hi !
Wich year and month you see thid article ?
To make this loco in HO a good start it's with a athearn SW7, you keep only the walkway, the cab are from canon ( it's not 100% accurate for this model but it's the better) the long hood probably atlas... if you check recent subject i ask for GP7/9 information, it's for make this locomotive.
With the juneco SW1200 detail kit and other detail pieces you can finish the model.
Thanks !