What cirteria do railroads use to determine which engiene types to assign to a particular type of train (e:g. manifests, coal drags, local trains, IM trains, etc)?
Horsepower per ton to be hauled based on priority level of commodity to be hauled (i.e. how fast do you need it to get there), tractive effort (i.e. lack of potential for wheel slip on grades, etc.), reliability of the locomotive(s) in question (i.e. are all the units in good shape?), equipment installed on each unit (i.e. are they “lead certified” with radios, etc.). These are but a few of the possible considerations a motive power superintendent may have to look at.