Mid-tier alcove bridge

Not much new to report. I've started building the plywood subroadbed for the rest of the middle tier of staging. Just one picture to add:


Previously I mentioned that there is a 3' 9" wide alcove that the staging tracks have to span without supports because I will later want to be able to crawl under the track to get into the alcove. In that previous post I had a side picture of the upper tier alcove bridge. This picture above shows the underneath of the middle tier alcove bridge before it has been installed, so provides a better view of the bridge construction. (Note that the bridge is temporarily resting upside down on another part of staging -- this is not where it will be installed.)

There's not much to this construction. Two L-girders are attached together with nuts and bolts to provide a level surface, then the L-girders are attached to the underside of the plywood with #8 metal screws and washers. The plywood is strong enough to hold a whole slew of N-scale trains but it will tend to warp/bow unless something keeps it flat and level -- the L-girders provide that service and also provide some vertical strength in case some doofus like me stumbles and lands on the bridge.

Next step is to finish the subroadbed and add the blue roadbed -- I can complete both tomorrow if I can get a free hour to work on it.