The Helix Build Thread – Part 5
September 27, 2011
With the transition from flex track to curved set track completed in the last stage, progress on the remainder of the first loop of the helix proceeded as follows:
Completion of the first loop of helix
1. Glue foam roadbed to helix curves using Foam Tack glue. Perform this step prior to installing helix curves into towers.
2. Prepare curved set track units in advance by a) soldering two curved sections together and b) soldering 22 AWG feeders to the completed track unit.
3. Glue in Towers 3B. and 4B and, before they set, glue in the third and fourth quarter turns of the first loop
4. Before glue sets make sure that the end of the first loop aligns exactly over the entry ramp of the helix below it. Use clamps and squares to ensure that Towers 3B and 4B are true in the vertical plane as the glue sets. Towers 3A and 4A can be placed in position for support while glue dries but should not be glued in themselves.
5. Prepare the red and black “branch” wires for the second loop. Cut wire to approximately 70 inches long. Strip and solder to vertical “trunk” bus wires approximately 2 inches above the point where the first branch bus wires diverge from the trunks. Soldering two sets of stranded 14 AWG wire is a bit challenging as it is difficult to get sufficient heat into the dense mass of wire to fully melt solder deep into the join. A high powered soldering gun is essential for this and even then it requires patience and lots of flux and solder to form a firm join. Clean all joins and wrap in electrical tape.
6. Use Foam Tack glue to mount the previously-prepared Peco curved set track units on to the roadbed. Connect the 22 AWG feeders to the second loop of branch bus wires. This completes the first loop of powered helix track. Test under DC power. The looping branch bus wires should supply a constant voltage to the helix track via the track feeders. Locomotives should ascend the loop at a constant speed as a result.
7. Add additional lateral support between towers. While the design of the Ashlin kits is generally solid, the lack of support between each of the four tower pairs may result in the outer perimeter of the helix drooping downward and outward. This could cause uneven track and may lead to derailments.
Use scrap lumber to add supports under the helix at the 45 degree points (i.e half way point between towers). A small level placed across the track is makes it easy to detect and fix lateral deviations. With extra support installed the track should be consistently level in the lateral plane around the entire first turn of the helix. Note that the process of propping up the helix at these points may slightly stress the glued-in towers and push or pull them out of the vertical plane. This can be corrected during installation of the second loop
Extra supports added underneath the helix between towers
