Not sure if I titled this right, but here goes....

Need some advice/help on how to keep a drill bit plumb (or vertical) when drilling through foam/benchwork.  

Here's the deal...  I have 2" of foam on top of a hardboard surface (supported by 1x3 gridwork).  My layout is entirely flat  urban/industrial, etc.  In a city portion, I want to install streetlights.  I have a devil of a time keeping the drill it plumb (perpendicular) to street/sidewalk surface.  

So I'm cleaning up the layout room, and I realize I have a $hit ton of empty Athearn, P2K, Branchline, (the list goes on) of empty boxes for mostly my cars on the layout, but also some engines, too.

Since I'm a bit of a hoarder in the sense that I think "hmm, I may need those one day", my question to the group at large is, "Do you keep yours after you empty them?"

So, Jimfitch and I were discussing Value Trains and agreed to disagree on that topic. An intriguing aside to that is this: What is the best model F-unit, and also what do you consider the worst? My picks are the Highliners kits, my least favorite is also probably the most common, the Athearn Blue Box.  Reasons, Highliners set the bar high and the ability to detail to a specific prototype.  The Athearn because the early drive was only able to go at warp 5 until the  rubberbands broke, and the shell is inaccurate especially the windshield.  So lets have it!

So, I'm in the process of designing my new layout (large scale outdoors) and workshop space in the new house, and I've got a design problem, I need help with.