Helix construction

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Hello all.

Well I am off building my helix to get to the second level of my layout. I am using a technique I read about in model railroader. In fact I have seen this style of construction at least two times that I can remember.

It is a simple way to build a helix. You cut out the subroadbed with a jig saw, and use spacer blocks to create the seperation between levels. Once the intial grade has been achieved (2% for me), the next levels will adopt the previous grade as you go along. I still think this is one of, if the, simplest techniques I have ever seen.

The hardest part about this project (for me anyway) has been creating the 2% climb with the risers on the first turn of the helix. I had no success with the helix in place. I have had to go with the risers alone creating the 2% grade using my lelev and the %/degr tool I have bought form Micro Mark (fantastic little device I might add).

As usual for me, a little couple of hour project has turned into quite the frustrating nightmare. But going from one riser to the next in this fashion has given me a steady rise that , when finished, should give me a good starting point for the bass of the helix. I can go along and make adjustments when I finish.

I am hoping that I will have some good noews tomorrow night.

Any thoughts?

Jim

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LKandO's picture

Helix Construction

Take a look at George's helix construction post: model-railroad-hobbyist.com/node/4205

Alan

All the details: www.LKOrailroad.com        Just the highlights: MRH blog

When I was a kid... no wait, I still do that. HO, 28x32, double deck, 1969, RailPro

Sugar Beet Guy's picture

More detail on my helix

Here are some detailed shots of my initial risers.  I used 16 risers and I calcuated the elevation needed for each one.  They were carefully measured and cut on a chop saw including the 2 degree slope on the top. After double checking with some plywood helix segments (and recutting a couple - "measure twice, cut once"), they were glued and screwed in place.

 

George Booth
Director of Everything, The New Great Western Railway
http://users.frii.com/gbooth/Trains/index.htm

Sugar Beet Guy's picture

Actually, 12 risers

My bad.  I had 12 risers around the helix, not 16.  I wanted to clarifty that in case there are riser counters out there waiting to pounce 

 

George Booth
Director of Everything, The New Great Western Railway
http://users.frii.com/gbooth/Trains/index.htm

Rio Grande Dan's picture

Riser Counters

LOL now that was funny!!

Dan

Rio Grande Dan

JKtrains's picture

Risers

For my helix I determined the vertical rise for 1 turn (4") from railhead to rail head.  Therefore for 1/2 turn I needed to rise 2".  I cut a block of wood exactly 2" high and then used a long, straight board to span across the helix from one side to the other.  PLace the block of wood under the board on the lower side at the starting point of the helix grade and adjust the riser on the opposite side until the board is level.

Another helpful, homemade tool is to cut a short length of board (something like poplar or oak) between 9" to 12" long.  Mark the centerline down its length and extend the line down each end.  Drill a hole at one end thru the centerline and insert a T nut.  Thread a nut and a 2" carriage bolt.  Thread a nut onto the portion that sticks thru the top.  Now us the same long board to span across the helix, but this time without the 2" spacer block.  Place a torpedo level on top of the short board and place it on top of the longer board.  Adjust the carriage bolt until the short board is level and use the bolts to lock the carriage bolt in position.  You can use this to check the slope/grade at any point of the helix's first and can adjust the riser to the proper height to have a constant grade throughout the helix.

cv_acr's picture

 That's pretty much exactly



That's pretty much exactly how we set the base grade for this helix at the club layout as well:

After that, it was simply using standard 3" blocks for each turn, creating a consistent grade for each loop. The key is getting that first turn graded properly before building the rest of the helix.

bear creek's picture

Thanks guys for sharing the

Thanks guys for sharing the photos. They make it really easy to understand the methods you're using.

Charlie

 Contributing Editor, Model Railroad Hobbyist magazine

Vertical easement

I hope this is not too late - don't forget vertical easement either in the helix or in the tracks leading to the helix.

Steve Raiford


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