Mike-
Thanks for the sad photos. I drove down Elston a few weeks ago and was thinking it was amazing that the track was still in place.
The track down Wabansia was actually part of the Milwaukee Road. It served the Proctor & Gamble plant where the track split into two and both sets of tracks entered the building from the west. Milwaukee Road hauled out finished goods while the C&NW delivered raw materials by a track that crossed North Avenue on the south.
The building in the background in this picture of yours shows the two entrances the Milwaukee Road used. The building now is owned and operated by the City of Chicago. The rest of the P&G plant was torn down.
http://www.flickr.com/photos/36106399@N04/5608778274/in/photostreamThere used to be an interesting puzzle switch east of Elston on this track. You could see the faint outlines under the asphalt. Do you recall seeing any turnouts on the ground without switch points?
Even prior to P&G Illinois Steel had a plant at the same location which was served by an isolated EJ&E operation. The current Mill Yard-still in use by the Chicago Terminal to shuffle gondolas-was originally the Rolling Mill Yard since it serviced shipments to and from the Illinois Steel factory. The C&NW and Milwaukee Road both had access to the Mill Yard but P&G was always served by the Milw Road on the north end.