SPLINE HELIX UPDATE: Back a few months ago, someone asked about how engines and cars would be prevented from falling off of the helix.  Originally, I thought about using cardboard or hardboard strips.  However, their use would have reduced the narrow opening between helix turns so I looked around the garage and found some left over screening (nylon or fiberglass).  I also bought some white poster board from a local office supply.

What you'll see in the next few pictures is a mix of screen and poster board covering "view sides" and "non-view sides"  of the helix.  I had decided that I would leave an opening in the fascia (when it is mounted) on the open end of the helix near the entry door to the train building and another viewing area on the side facing the peninsula.  Those portions of the helix that would not be in the viewable areas would then be covered with poster board.  The poster board was extended about 2 inches above the track where I needed a safety block from the edge.  I attached both the screening material and the poster board to the side of the spline roadbed with small furniture upholstery tacks using a tack hammer.  The tacks readily went into the hardboard since they have a pretty sharp point.

The first picture is the "viewing side."  I have not yet decided whether the top loop above the helix will be one track or two so I'm leaving it bare for the time being.

The next picture shows the "non-viewing side."
 

The picture below shows the end of the helix that will be near the entry door to the train building.  The poster board side will be against the wall.

Finally, a picture from the inside of the helix.  The inside will also be covered with the same screening material but will be attached to the side of the spline roadbed using "velcro 5/8" stick-on buttons" purchased from a fabric store.  That way, I will be able to remove the screening to either put a car or an engine back on the track or clean the tracks.

 

I am now finishing up the adjustments of the threaded rods on the second helix and plan to install the screening and  poster board. 

UPDATE ON STAGING AREA: The base table of the peninsula has now been extended to its full length of 18.5 feet as shown in the picture below.  Note that I have pre-drilled holes for wiring in the cross members (they can be seen better in the second picture).  I do not know whether I will use all of them but they are there since it is easier to do it before assembly than crawling around under the table to do it later.  

During July, I will finish preliminary wiring of the two helices and continue work on the staging area which as to be finished and tested before the main level is begun.

Please don't hesitate to ask any questions.  Thanks.

John