I am told by a viewer that is a tender for a steam engine carrying either coal or oil. That explains the number 786, a steam locomotive now being restored for use in Central Texas.
In the days of steam engines - yes that's a long time ago, they went out in the late 50's, this was the tender - basically the fuel tank - for the steam engine. It was attached to the steam engine. In way back times, it was a square box which held coal, toward the end of the steam era, many railroads switched over to oil.
If memory serves me correctly, SP 786 belongs to the Austin Steam Train Association, in the process of being restored. See their websitehttp://www.austinsteamtrain.org/trains.php
