I am pretty certain that the units term came from the manufacturers, but not necessarily in terms of a locomotive. In the early days of Es, Fs. FAs, PAs, etc., locomotives were made up of multiple sections or components called units. An FT freight motor might be made up of four units comprising one locomotive, particularly when drawbars were used instead of couplers. Then, we MU (multiple unit) them together with an MU cables connected to the MU receptacles to make it one locomotive. It was not uncommon in diesel shops or roundhouses to hear references to units available or even little or big units with reference to horsepower. A few older books even referred to steam locomotives as units, but the more common terms were locomotive or engines. I think the best way to think of the term is as units of power, but in most cases, each diesel unit is capable of being a locomotive if it has a full cab with appropriate controls. Over time, the terms locomotive, unit or engine have become interchangeable. An engineer might say that I have three locomotives today, or he might say I have three units or three engines. Everybody that needed to, would know what he is talking about.
Gravois Mills, MO
Mon Jan 13, 2014 8:45 am (PST) . Posted by:
And how about locomotives being called "units"?