I have searched through the posts and thought that the answer was simple until I read that certain dc locomotives can be more difficult to convert to dcc depending on whether the motor is isolated (not sure exactly what that means) from the chassis (I assume electrically). 

My daughter has an older (just a few years) EMD FT Diesel (Santa Fe - red and silver) that is strictly DC that I would like her to be able to run on my layout.  The instructions have the following number on them H620X-IS001, but no serial number is visible on the actual locomotive.

I happened upon a Bachmann 1 amp decoder with wiring harness (Bachmann item number 44913).  I am not concerned about soldering, having made other projects in the past.

My questions is if the decoder that I have should work, or if I am wasting my time with the locomotive in question.

Any help would be appreciated.

Sincerely,