Add detail to boxcars with open doors.  Add some crates, boxes, tarp load, or figures to your boxcars that have open doors.  There are even lumber, barrel, or bag loads you can place into an opened boxcar.  You can even add a fake wood flooring to add more detail.

Micro-Trains Military Barracks Build by Modelersguild.com

Building this Z-Scale kit was a real pleasure. The parts fit nicely, the materials were right, [ ... ]

The sawmill has a permanent place in our hobby as an industry built in the sticks. The location of these structures usually is located far from civilization [ ... ]

or why did I decide on Z-Scale model railroad.   

    I had been dabbling in N Gauge off and on since 1974, when I gave [ ... ]