The Helix

2/10/21

Last report we indicated the helix had been “corked” and rail would go down this week. I’m happy to report that it did. The crew of Doug, George, and Gene, helped me glue down a piece of flex track almost 25 feet long and done all at once! We did this to insure against kinks in the curve. It took some serious preparation and genuine concentration to make it happen but it turned out to be a beautiful 49” radius curve. Moreover, it was on a 1.7% grade and we had to get it right – curve, grade, consistent radius. This curve serves as a base for the rest of the helix and must be pretty accurate. Most of this progress report will be about the process leading to a serviceable helix circle. After setting the sub-roadbed (plywood) and roadbed (cork) we started getting ready to lay in the track. Gene soldered up several sections of flex track 2 pieces long or about 6’. We would need 4 of these long sections plus one 3 foot section. Next, I temporarily laid these long sections of flex-track on the cork and soldered the joints.  After connecting this 25 foot long snake I set it off to the inside of the  curve on the sub-roadbed. The crew was summoned, each given a 6” wide sheetrock paddle and stood at the ready. I shot a 3/8” bead of  Polyseamseal (clear latex caulk) along the inside edge of the cork and we all went to spreading. Short side to side strokes made quick work of the whole circle. Pursuant to my previous instructions, the boys picked up the 25 footer and held it over the cork. I went along laying the track in the center of the cork as the crew fed it to me. In short order it was all down. 

Doug, Gene, and George caulking the helix in preparation for laying in a 25 foot  piece of flex rack. 

Figure 2 George and his roller. ever in creasing pressure insures that track is im bedded in caulk but not pushed out of  alignment.

Using a small compact mirror (3” x 4” ) I sighted the curve and  all looked well. Next step was a 1” neoprene roller and I lightly rolled  the track. Then George went over it several more times to insure good contact. 

Lonnie came by later that afternoon and we powered this  section of track so he could test it. After some experimentation we found that his engine, a Kato 4 axle RS-3, could pull 16-18 cars up the grade. On the old helix Lonnie reports that it had a 12 car limit. On  this helix the engine did really well except in one location where it routinely stalled. A helix problem had become apparent. 

Figure 3 Here is a close-up of a helix ad justment. Note the stringer and riser (just  visible below rear engine truck. In front of  riser is an “adjustable riser” with the diagonal  cut. This allows us to push the sub-roadbed up  in very small increments.  

This morning Doug and I went to the club with another lightweight engine (Athearn GP-7) and tested for consistent operation. We identified the slip out location. We put a  straightedge across the plywood and found it to be a bit low causing a hump in another place – right where the engines stalled.  Before checking the actual grade in this location we re-leveled the  “L” girders using levelling screws in the bottom of the legs. This further defined the problem area in the sub-roadbed. Releasing the screws from the sub-roadbed into the top of the riser, allowed the plywood to adjust itself. It also caused another problem area.  We adjusted both areas (see figures) and re-tested with a train. 

Now folks, it’s been 5 months or more since we ran a train on the club layout. I tested the helix several times and then Doug wanted to re-test it – several times. About then Gene came by and he wanted to re-re-test the helix – several times. That poor old  Athearn GP-7 went up and down that curve many times as we  “confirmed” test results. I’d say that curve has been thoroughly tested. In fact, we tested it to full locomotive slip-out – quite a few times. Those wheels were SHINEY!  Not only did we have glistening wheels but the code 83  (.083 high) rail is now probably about code 79 (.079). In other news, Doug and George re-set the grade into Eddyville. After a bunch of hard work they have all of the mainline sub-roadbed installed in the north room!