The Helix Part III …
Since the last post, there’s been more movement on the helix build.
My package of PECO Code 75 flex-track from the UK arrived on Monday (30th). Before anyone starts on about why I didn’t buy it locally, I’ll tell you why. I got fifty 914mm (3ft) lengths delivered from the UK for $173.75. A quote I got from Brunel Hobbies in Melbourne was $176.60 (posted to Port Macquarie) for 25 lengths – double the price!! Why should I buy locally? If importers in this country feel the need to put such huge mark-ups on items sourced from overseas, is it any wonder they are complaining about internet sales taking away their business. I won’t say any more on the subject.
Anyway, back to the topic at hand.
Before track laying could commence, I had to build part of the first section of spline that would exit from the helix and continue on towards the storage yards. So, I did the usual thing of marking out where it would go using measurements from the 3rd Planit drawing. I also made a short transition piece of helix roadbed for the spline to attach to. I decided to only make a short section of spline so I could later remove it to rebate the top where it meets the helix.
Whilst the spline was being made, I mulled over how to start laying the flex-track. It’s funny to think that I have never really laid any flex-track in all my years of modelling. Anyway, first step was to mark a centreline on the helix roadbed. I then spent some time thinking of the best way to lay the track. As I would require joins on curves, I didn’t really want to just ‘butt’ join the sections as this generally does not allow for a smooth curve through the join. So I decided to stagger the joins. With PECO track, both rails are able to slide through the moulded chairs, so I pulled one rail back about nine sleepers, and cut away a couple of sleepers where the join would be. As I didn’t have any PECO rail joiners, I did the next best thing – a short piece of 30 thou brass wire soldered to the outside of each rail. Two lengths of track were joined together whilst straight.
Some more time was spent deciding on the best adhesive to use to fix the track down. I wanted to find something that would glue the plastic sleepers OK, be a strong bond, be fast setting but allow time to finalise placement. I didn’t want to be waiting around for hours whilst glue dried. After heading to Bunnings and looking in their adhesive section, I finally decided on a Selleys product called Aquadhere Quickset. It sets in about 5 minutes but fully cures in around 30 mins, is water-based and dries clear.
I also had to think about how I was going to hold the track in position in the curve whilst the glue dried. I decided to use small panel pins. This PECO track does not have any holes in the sleepers, so I drilled every tenth sleeper to make a neat fit for the panel pins.
Next, the track was placed on the helix roadbed and formed roughly into the correct curve. I managed to find a Tracksetta 36 inch radius template which will do the job nicely.
So basically, it was just a matter of placing the Tracksetta between the rails, ensuring the track was on the centreline and using the same small drill as before, drill a hole into the roadbed. The small panel pins were then pushed through the sleepers into the roadbed.
I also found out that my plan of using two lengths of track pre-soldered together was not the best move, as there was a bit too much pulling of the rail through the sleepers to adjust things on the curve as I went. For the next and subsequent layers, I’ll lay just the three foot lengths in turn. It’s much easier to pull the rail through the chairs in three feet rather than six feet.
The section of spline was removed from the benchwork and set up in a jig to allow for the rebate to be made to allow for splicing to the helix roadbed ply.
The picture below shows the spline now back in situ and glued to the helix roadbed. The spline was also set at the correct grade which at around 1.8%, is slightly steeper than the visible section of the layout but should still be OK. This is the same grade as the helix.
I decided to only fix in place a short section of track on the spline merging with the helix track, so I cut a strip of the foam tape roadbed and glued it to the spline. The foam was cut to the width of the spline, but to allow it to follow the curve, some cuts were made about 75% of the width to allow it to curve and remain flat. The cuts are just visible in the image below.
Another length of track was cut to splice into the section already tacked down on the helix. Some extra support for the spline was also installed here.
Today (6th) I glued the first layer of flex track down on the helix and the spline. For the spline section, I used some black caulking compound as a trial, as I was unsure how the Aquadhere Quickset would fix the plastic sleepers to the foam. A lot of articles I have seen about laying the Central Valley tie strips to foam roadbed mentions using caulk. The Aquahere Quickset was used on the helix sections though. Using a thin metal spatula, I carefully levered up the track a small amount, still making sure it was held by the nails. The glue was then dribbled over the sleepers, and using the spatula again, smeared underneath the sleepers and over the timber. The track was then pushed back down firmly. No weights were used to keep the track down as the nails were a firm fit in the holes in the sleepers, and seemed to hold OK.
Within half an hour, the glue had set enough for me to be confident the track was held in position. I then decided to start the next layer of helix roadbed. Some small blocks were cut to hold the new layer above the first whilst being glued and clamped.
With the number of clamps I have, I can only do about three segments at a time, but it should proceed reasonably quickly. Once another roadbed layer is complete, the tracklaying process starts again for that layer and so on until I end up with five layers of helix roadbed with track attached sitting on top of one another. The next stage will be to notch out the support risers, fix these in place, and lift the levels to the correct positions but that will be described in a later post.
I did also think about soldering the track feeder wires on prior to fixing the track down, but I think I can do this later.
Cheers for now.