Helix Radius

[johncolley]

To the best of my meager knowledge a switchback is like a "Z" sometimes with several layers. it works like this: you proceed to the end of track, the switchman or brakeman throws the switch (turnout)behind the train, you back uphill to the end of that leg, the head end brakeman throws the next switch in front of the loco and you go forward uphill, repeating as many times as it takes to get to the summit, over the ridge, or up to the mine. It is rather like a skateboarder going back and forth to get from one end to the other, eh? Only up the side of a hill.

[TomDiehl]

Our club built a helix on the HO layout several years ago. This one is 4 tracks wide, 5 levels, and radiuses are 36 to 46 inches. We used 1/2 inch plywood, no road bed, code 100 flex track. We made the supports out of threaded rod with nuts and washers above and below the support point to hold it in place and to allow for the inevitable adjustment for aging. The operation has been relatively reliable for the several years we've been operating it. You have to take a GREAT deal of care in the construction stage. Pay particular attention to smooth joints, steady turn to the track, flat roadbed, and TEST AS YOU BUILD. We have almost 4 inches between the levels and sometimes this is too tight for rerailing items. Remember, Murphy's Law is strictly enforced in model railroading.

Our club is located in Stockertown, PA Our website is http://nasme.tripod.com