7 inches of clearance to have

7 inches of clearance to have to get in and install tracks 2 feet back will be tight. Even if you can install it first and position the shelf, cleaning said tracks or getting in for maintenance will be challenging.

N scale often gets us into situations where the trains fit, but the human parts needed to ocassionally assist the trains do not.

Can you add a loop or two to the helix, or increase the grade in it to widen the separation?  I'm more inclined now that I am older, and my back makes more noises, to avoid gymnastic approaches to accessing tracks. Hiding the staging behind a backdrop could work, but think it through carefully so you can be sure the backdrop removal isn't too much of a hassle.

Lots of good modelers have trended towards open staging or easily accessible staging for good reasons. 

I just decided not to build a layout plan that I had 75% of the benchwork installed for because one major staging area would have to be totally hidden under a sceniced level just 6 inches above the staging yard. Trains will fit fine, but even with removable scenery sections, the thought of accessing that staging yard was enough of a concern to rethink the entire design.

7" is really not enough

  Once you factor in the thickness of your bench work, There will not be enough room for your hands.  Even super thin bench work in N will be at least 2" thick.  Normal bench work with traditional 1 by 4 construction will be over 4" by the time you add up the roadbed/track and the framing.

  My old HO layout had 4 staging tracks 6" higher than the scene in front of it.  This took up 8" of space, and I had another 22" of space for the large bluff and the town below and in front of it.  The bluff extended about 2" higher than the staging tracks.  With trees, one did not see the staging track unless they were looking for it.  Access was good, but it was easier to pull the trains out to stage everything for the next operating session.  The biggest issue was not enough staging tracks!  Adding more would have moved the front scene out, and the 'reach' to the staging area would be difficult.  With N scale, you may be able to do this.

  The current layout(under construction) has a helix that drops from 54" down to staging at the 36" level.  I have 10 staging tracks in a 24" wide space(and 15' to 17' long).  That 18" 'rail to rail' difference is eaten up by 4" of upper bench work/fascia and lighting for the staging(to be installed).  I will have about 8-10" of space from the top of a freight car to the bottom of the upper level when everything is complete.  Now, consider your 7" of space.  If you are going to use a helix, add as few more turns and give yourself some room!

Jim

Thanks for the advice

Jim and Peter,

Thanks for your thoughts.  I definitely don't want to give up staging tracks.  I will add a few more turns on to the helix and move the layout from sitting height to standing height.  What are your thoughts on 12" of separation (rail to rail) with 2" foam on brackets (with plywood L girders extending the bracket to the edge of the layout) every 16"?  A second consideration is to use 1 1/2" foam with 1/4" or 1/2" plywood under it for a little more stability??  I m planning on making the turnout and servo one drop in piece, so having something solid under the foam is not as important.

Thanks!

Ryan

Ditch the L girder

Ditch the L girder construction above the staging. A simple shelf bracket is sufficient to support N scale benchwork, a tip I picked up from a book on double deck railroads. With the L girders, your 12 inch rail to rail gets chopped by the 2 inches of foam, 1/2 inch to plywood, and then 3 1/4 to the 1x4 L girder, so it winds up with 6 1/4 inches of clearance.

Sorry, I may have confused you..

Peter,

Sorry, I may have confused you...  I am just planning on putting a L girder on the bracket to extend the bracket the whole width of the layout 18" instead of the 11" the bracket will cover.  I am thinking 2" of foam, no plywood, and 2" - 3" of L girder perpendicular to the wall/front of layout.  I'd have 10" of clearance except where the grider comes out.  I may add one more turn on the helix to get to 14", then I would have room for facia on top that wouldn't impact the staging area quite as much.

Thanks,

Ryan