Train of pack burros in Mexico
http://digitalcollections.smu.edu/cdm/singleitem/collection/mex/id/678/rec/4 “Train of pack burros in Mexico” Calling the pack of a burros a “train” implies the animals as a means of transportation. However, if they are for transportation, why the man walking in the field not riding a burro? He could just be walking in order to keep the burros heading in the correct