The REO Speed Wagon was an early light- model truck, a forerunner of the pick-up truck.

First manufactured in 1915 by Ransom Eli Olds (“REO”), the Speed Wagon became one of the most popular motorized vehicles of the 1920’s.

https://en.wikipedia.org/wiki/REO_Speed_Wagon

Below, I have attached a Wiki free-use image of a 1917 Speed Wagon.

In this postcard photograph, the term,”Speed Wagon”, is applied to the ox cart.

The sturdy conveyance is attended by two rural laborers.

For rugged terrain and very heavy work, however, a mountain farmer might continue to depend upon oxen.

A little research uncovers some interesting information about the utility of oxen, and some reasons for their continued use.

A team of oxen cost less than a team of horses, but retained their value better.

A team of oxen can pull a heavier load than other beasts on the farm – horses, mules, or donkeys.

Oxen are slower than horses, but pull steadier, even if they cannot cover as much ground.

A subsistence farmer would find that oxen could be fed more cheaply than any other draught animal.

(Almost three-quarters of the pioneers on the Oregon Trail used teams of oxen to pull wagons.)

https://research.colonialwilliamsburg.org/Foundation/journal/Spring08/oxen.cfm

This postcard photograph was published by the Asheville Postcard Company of Asheville, North Carolina -a prolific publisher of postcards.

Entitled, “The Mountaineers Speed Wagon”, the reference to mountains is certainly to the Appalachians.

The postcard was not mailed; one assumes that the collector was amused by the comparison to the motorized “Speed Wagon”.

Although more oxen are used around the world today than at any time in human history, agricultural data from the US shows only a few thousand oxen still employed on contemporary farms.