NTS & B Helix final attempt

June 2005 to June 2006- The second and final attempt resulted in 6 inch layers (top to top). It has 2 loops. An inner loop of 0-42 diameter track, and an outer layer of 0-54. This resulted in a 4.5% grade on the inside loop, and a 3.5% grade on the outside loop. Although still steep, it is workable. My postwar 2037 will pull 4 (well oiled) postwar passenger up the outside loop. My modern Lionel PA1 handled the B unit and 6 passenger cars. I had to add 1 more layer to maintain the desired height (around 30 inches). Ended up using 2 complete sheets of 1/2 inch plywood. I used 3 ply 1/2 inch plywood for the surface. If I had it to do over, I would use 1/2 inch 4 ply because it is stiffer in both directions.

Overall dimensions - 6 foot diameter, 30 inches tall


The picture above shows a temporary loop connecting the inside and outside tracks of the helix. This will eventually be stretched to go around 1/2 of the top of the room (App 16x20 loop).

The center picture shows a 2037 pulling 3 well oiled post war passenger cars up the grade.

The bottom picture (a year later) shows the planned loop the the bottom of the helix. This will be at table top level around 36 inches from the floor. The year in between was spent arranging for heat and air, and having it installed.

01/16/2011 update:
I suppose it would be a good idea to add the results of the helix outside loop testing. Tests were done using the 7 Polar Express passenger cars, up to 5 additional modern passenger cars, and a box car added to diesels to simulate the tender in the steam engines. Results are as followsL
-Polar Express and most other modern engines pulled up 12 cars or more. A couple of the dual motor modern engines acted like they could pull many more cars without issue.
-624 swither (with magnitraction) only pulled up 8 (plus a simulated tender).
-2026 2x6x4 pulled up 6,
-2020 6x8x6 pullted up 5,
-2037 2x6x4 slipped with 4,
-2018 2x6x4 slipped with 3.
-Also, if I remember right, the 2020 would slip when pulling only 4 well lubricated postwar passenger cars.
-Another note, coming down on the inside is fun also. The 2020 had to be run at such low voltage that the e-unit kept dropping out. To run unattended, cruise control is almost required (which includes MTH PS2 and Loco Sound engnes). The exception is a very low geared engine that won't speed out of control on the way down.