Hard to say, all those early DSP&P tanks seemed to be like those of the D&RG up on Marshall with the fully enclosed understructure and the Tender toolboxes hide this view. I too noticed those footings years ago on a pilgrimage up the Platte. Interesting to see the road is now sealed and those supports still remain on Streetview {:))
http://digital.denverlibrary.org/cdm/fullbrowser/collection/p15330coll22/id/78053/rv/singleitem/rec/4
UpSideDownC
in New Zealand