Regarding the tan color and to a lesser extent the Bordeaux red color being used on the L structure, I've never understood why the resistance to going really dark much in the same way that so many exposed joist/rafter ceilings in commercial/retail spaces or even residential basements are painted dark to "make all the mess go away" by obscuring the assortment of conduit, plumbing and additional bracing structure just sort of disappear into shadow, especially in a low light/down lit environment.
As someone who has actually set down and read the entire NYCT elevated structure repainting RFP guidelines .pdf for potential contractors, I know there is actually a lot of science behind the choice of paint for structures, not just a color coatings fade resistance but a slew of very specific prep and application requirements to assure, ultimately the taxpayer, that the applied point will last as long as possible. The MTA in NY had a high profile fail several years ago when the red paint job on the Hell Gate Bridge started to fade terribly within a couple years I believe and it still looks like crap. I'm sure they learned a few things about that choice and are doing everything they can to prevent it, though I understand there was some claim by the company that supplied the paint that it was the contractors fault of something, I dunno.
Anyways, this gets me back to just a general desire to see some elevated structure in Chicago painted out in a really snazzy sophisticated dark shade of something. A really dark evergreen green, a charcoal or this years "color of the year" "Urbane Bronze"... the kind of shades that would go a long way in obscuring the quite unattractive utility underbelly of the structure. And after saying all that, I'd give it all up to see the L structure painted Swamp Holly Orange:
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