Benchwork Joists

At this point, you’ll need to take into account exactly where the subroadbed will be located (or as best you can).  I got all of the subroadbed pieces for the left and center parts of the top level glued into one large piece first.  Then I laid it on top of my L-girders in as close to its final position as I could.  I glued all the subroadbed parts for the right half into 1 large piece and then laid it on top of the L-girders on the right part.  Lastly, I glued the large left/center piece to the right piece to get 1 huge piece for the top level.

I had to take this approach because the track passes through the 2 backdrops that run down the center of the layout.

With the entire track plan now sitting on L-girders, I could see where it would be best to place the joists.  I kept in mind that, wherever a joist crossed the subroadbed, I would likely be installing a riser & cleat.  In particular, I was careful to avoid putting a joist close to where a turnout was going to be located.

Onto the L-girders, I laid as many joists as I needed to properly support the subroadbed.  Each was laid on edge and at something close to a 90° angle relative to the L-girders, but I put some at weird angles and all was fine.  The joists were 1×3 poplar.  I screwed them to the L-girders from underneath.

My goal was to have a joist every 12″ – 18″.  Any closer and it gets tricky to get a drill into place.  Any longer and you risk have the subroadbed losing its stiffness.  Please note that these numbers are based on the subroadbed being made of 1/4″ Baltic Birch.