I've found many, many articles on painting bricks but not much on painting concrete blocks. 

I've found Tom Johnson's Feller's Garage post but his blocks end up being painted white and other colors. The weathering part is helpful though.

Unfortunately, walls don't look like this for every long:

They get stained, have white stains and the mortar ends up darker.

Joe Fugate's book on trackwork has much sage advice, and a focal point is frogs in chapter 10.  The merit of dead and live frogs is discussed, along with the frog juicer.  Frogs are often considered amphibious swamp creatures, so all this talk of turnout frogs got me wondering about the term's origin.   Some wikipedia info:

https://en.wikipedia.org/wiki/Railroad_switch     excerpt:

I am building a Fremo module of a Canadian grain handling facility.  Not modeling any one in particular but using details from several.  However I am struggling to find some of the trackside details, like these hand thrown  switch machines in 1:87 scale.

Well here is the final project for the year. I Kit bashed a Highway Miniatures Erie B-2 Steam Shovel into a Marion Type 450. HBMS had 10 of these versatile units.

I used almost everything from the kit with the exception of the boiler.