All the boxcars in the pic are DRG of Sloan's class 3 but one. Can anyone tell where 1789 came from? DLG comes to my mind, based partly on the blacked out lettering and drawhead arrangement. DPL has a question mark after their 1900-1910 date - makes sense to me that these were all being collected from DRG and others (like DLG) at Pueblo in 1891 for delivery, except that 3496 looks like it has a shop date of 4-93 on it.
Also note the string on the left is airbrake equipped and has (presumably former) DRG3449 in it. Also someone left their sandals on the roof of 3496.