What is the correct use of the term "drag"

Oh... you mean like a COAL drag.  Whew.  Thought you were asking about something else.

Bad boy !  

Does anyone know if the term drag could be used for any long freight train? Or any freight train for that matter? Anyone know when the term was first used?

Well, it has been around over a hundred years.

Many low drivered freight locomotives from the first two decades of the 20th century were considered drag freight power.  They included 2-8-0s, 2-10-0s, 2-10-2 and compound mallets.  They typically had low end tractive effort but boilers of limited capacity, drivers in the 55 inch range and poor balancing of reciprocating equipment.  Speeds of 25 mph would have been fast, about 10 mph was typical and grades might be taken at a walking pace.  The idea was to hang as much tonnage on the drawbar as one crew could move over about a 100 mile district in one day.  And back then it was a 16 hour day.

All that began to change right about 100 years ago.  The USRA never bothered to come up with a standard 2-8-0, it was too old fashioned by 1917.  The USRA Mikes, like many of that era, had 63" drivers for better speed and balancing, grates of about 70 square feet for lower firing rates at medium and high power, combustion chambers and Type A superheaters.  They were smoother running, higher horsepower machines than the drag power that came before them. 

By the late 1920s steam locomotive technology had advanced even further.  Better lubricants allowed the use of higher temperature steam.  Better steel and the Type E superheater provided that higher pressure, higher temperature, higher energy steam.  Better steel also allowed for lighter weight rods that made balancing running gear at high RPM easier to achieve.  By the 1930s roller bearings (see 3rd Rail's beautiful model of the Timken Locomotive. https://ogrforum.com/t...11#38314881157697811 ) cast steel frames made superpower locomotives much less demanding of attention in round houses and shops.

By 1940 Berkshires, Northerns, high drivered Texas types and simple articulateds were combining heavy haul, fast freight and even passenger capabilities in one locomotive.  And they did it with greater speed and reliability than the locomotives of a generation or two before.  That meant that a single locomotive could run over several crew districts or be serviced, turned and back on another train before old drag freight power would still be trying to cover the first hundred miles.

If you have a shelf queen that is a model of a locomotive commonly used to pull a coal drag, does that mean its a  . . . . ?

Drag...the word, and a short but true story: 

I brought several college friends to the 'Big Easy' in '60. we toured Bourbon Street

and of course several clubs where there were amazing ladies performing amazing acts.

To top off the night I took everybody out to a place called 'The My Oh My' club where one

of the guys absolutely 'fell in love' with one of the performers. He parted company with us

and met with us the next morning with a black eye and said: 'uh, I see what you mean about them being in 'drag', I shoulda listened!' to your advice, Bernard'. 

Every year around Mardi Gras time I send him A greeting card with the signature,

'Gracie, your Drag Queen, hope all is well!'.

Thanx for the answers.  

Any train dispatched without sufficient horsepower to make track speed could be considered a drag freight.

An interesting and pragmatic definition that makes sense.  

My uncle worked out of Trinidad, Co and Raton, NM for ATSF.  As he got more seniority he used it to nail down assignments that kept him close to home, until for most of his career there he ran assist locos back and forth from Trinidad to Raton.

He used several terms I'm told were not commonly used all the time, such as referring to himself as "an engine driver" rather than engineer or operator, but I never heard him use the term "drag" with respect to railroads or locos.  He did tell me there was no locomotive made "with enough power to pull more than a few cars up Raton Pass faster than you can walk it."  I'm sure Santa Fe had a schedule for the Raton Pass segment of its system but some of the trains, even with two Mallets helping, took over 13 hours to make the roughly two dozen miles.  That strikes me as a good "drag" whatever they called it. 

Between about 1890 and 1910, the size of the largest available steam engine roughly doubled. Railroads decided that it was more efficient to run one HUGE engine with one long train than several smaller trains with smaller engines. Small drivered 2-10-0's, 2-10-2s and 2-8-8-2 Mallets were used to haul trains of previously unthinkable lengths.

The railroads mainly worried about how many cars could be pulled, not how fast, so these engines had fairly small drivers (51" or so) so couldn't go very fast. (IIRC a USRA 2-8-8-2 or 2-6-6-2 was limited to 20 MPH - it could go faster, but it wasn't properly balanced due to the small wheels, and could damage the track.)

When "Super Power" came along, engines with four-wheel trailing trucks and huge fireboxes, railroads realized they could get big engines with big drivers, and haul long freights at much faster speeds.

Thanks mjstix.  A good perspective on it.  

I think ATSF kept about a half dozen 2-8-8-2 Also locomotive they kept through WWII and for three of four years after to help assist long consists up Raton pass.  They had smaller drivers and lots of torque, and I have a few old photos of two of them helping one of the big 2765/2900 Northerns up and over the pass.  Talk about smoke!  Wow!