Coleman - Your post is unclear as to what you are asking. If it is whether it is common to use a particular locomotive in a particular application I would say no. Except when specific pools have bgeen developed because of service needs. Such things as 4 axle units for branch lines brecause of curve restrictions. Dispatchers and power distributors don't care what a unit is painted but rather what it's tonnage rating is. On the other hand other departments; like sales, PR, whatever, can and do have input as to the use of special units. The 1983 was probally at a place where it was needed to move freight and it was known that it needed to be in Oakland for the Sales Dept.(or whoever) event. The most efficient way is to use it to move a train that will get to where it is needed at the proper time.
If the question is whether it is common to put helpers in the middle of trains, it depends on lots of things. UP has a formula for the placement of helpers. There is also the factor of whether the helper going the entire crew district or cutting out short. If going the full territory, it would be possiable to run it with an engineer only. If it were cutting out short it would have to have a two man crew. And the list goes on. Andy