the MRH Forum

Cornhill & Atherton - The Helix Is In Journals/Blogs
Reply
MRH Contrib. Editor 1,931 posts fernpoint MRH Contrib. Editor 1,931 posts
fernpoint

helix.jpg 

The Helix Is In; which after my induction to the “top down” club at Christmas, was supposed to be the last job!

Following advice from Alan (wizard of LK&O)  I had a rethink and redesign of the helix.

By squeezing the headroom to 69 mm I managed to get an extra loop and therefore reduce the grade from 3 to 2 percent. This meant the helix no longer defined the railroad ruling grade – cheers Alan, a point well made……..

It has introduced some interesting clearance issues for the top deck, but that’s the next problem.

Since I have never built a helix before I decided to get this job out of the way first – that eases my mind that it all works (which it does) and firmly establishes entry and exit elevations.

So now its back to the original plan; top deck installation with Atherton engine terminal sitting directly on top of the helix.

Rob

Cornhill & Atherton (freelance 1930s Steam)
8x11, Double deck, helix and staging level
NCE DCC.
Reply 0
LKandO Prolific poster 3,839 posts
LKandO

Round and round they go

Glad I could help. Did you use the usual #4 wood screw and #8 flat washer arrangement to attach the track? I have been searching for a modified truss head screw to replace the screw/washer combo but I cannot find one with a sufficiently large diameter head without exceeding .083" height. A #6 pancake head is terribly close but no cigar.

I too have an engineering situation involving a helix. The topmost lap and the entryway are inside the benchwork instead of the usual below the benchwork. I have it engineered on paper, let's see if I am successful at making it real.

Alan

All the details:  http://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
nsparent.png 
Reply 0
fernpoint MRH Contrib. Editor 1,931 posts
fernpoint

Helix Headroom

Hi Alan

As you suspected, #4 screw and #8 washer used for track attachment. I picked that tip up from Jeff Johnstone.
Bit fiddly, but its a one time job and it works very well. I like the idea that even with soldered joints all the way up the helix there wont be any expansion issues due to temperature change.

Curiously enough my top helix lap also sits inside the top deck - that's my current conundrum.
I'll post some photos when the solution presents itself

Rob

 
Reply 0
Reply