Putting a lid on it - Updated

Since installing the helix, I have been pondering the best way to deal with the space it takes up, a square just over 1200mm. My basic options were to leave the area open forming a large unsceniced space in the middle of the layout or provide some form of scenic treatment which incorporates it into the layout as a whole.

Leaving it unsceniced would work from an operational perspective but would create significant visual distraction. The only advantage that the option offers is easy access to the top of the helix for maintenance but this can be achieved using other means. The option was discarded.

It was then a question of how best to scenic the helix. My though process was assisted by the owner of the Burrawon Branch Model Railway who regularly posts You Tube videos on various aspects of his layout. Recently, he published a segment on the scenic treatment of his helix. Burrawon Branch Model Railway The value of this video was that some of his stated objectives were similar to what I am seeking to do, specifically to disguise the top of the helix and to create a visual separation between the branch line crossing the top of the helix and the mainline using it.

My solution is not quite the same as the Burrawon Branch, rather I have decided to build scenery across the top of the helix with the Kingston Plains branch line crossing this area while the main line disappears into a tunnel.

While the top of the helix is landscaped, the sides of the helix will remain open for maintenance purposes. If I find this too distracting, I may fit a curtain around it but right now, I suspect that won't be necessary. 

The 'lid' has been built using my usual technique of mass styrofoam, carved to shape and then covered with very cheap absorbent towels from Woolworths soaked in a 50/50 mix of water and PVA glue. This serves two purposes. It contains any loose balls of styrofoam which sometimes break free and provides a suitable surface for the next step, covering with a various blends of coloured tile grout again mixed with a 50/50 water and PVA glue.

 I have incorporated a few landscaping elements which could not be included on the refurbished Philip's Creek station modules.The most significant of these is the Philip's Creek water storage tanks and treatment plant. I am also incorporating a small cameo scene on the upper helix loop to provide a little bit of interest on the outside of the layout. This sandstone cliff probably has more in common with Cowan bank on the Short North rather than the line between Singleton and Muswellbrook. The threaded rod will probably become a burnt out stump.  

It's still a work in progress!

 

Just a quick update to show the work of the last few weeks as the 'blue hills' have gradually been covered with tile grout mixed in a 50/50 PVA water solution. Much more detail work to do but this has broken the back of the 'bulk earthworks'.

"So this is Christmas"

It's come around again and this will probably be my final post for 2022 as the year rapidly draws to a close,  I'd like to take the opportunity to wish all readers  a Merry Christmas and a very happy 2023 for you and your family.

 

 

Building a Helix - Part 2 A few lessons learnt - Updated

Well, it wasn't quite a 'golden spike moment' or the completion of the transcontinental railway or Adelaide to Darwin link but last week, I finished the helix linking the lower and upper levels of Philip Creek. To mark the occasion, 4856, the oldest locomotive on the roster, collected a few wagons from the upper level and moved them to the lower level.

The concept of using an octagon shape to support the helix worked. I found it easy to cut and shape 540 x 125mm rectangles. Sure, the mitre saw got a serious workout but it was better than cutting circular strips. Originally, I intended to use 100mm wide strips but I found it needed to be wider at the octagon nodes. I wasn't too worried about getting the octagon geometry exactly correct. It was more important to get the circle within it laid out in preparation of the track laying. 

I did spend a fair bit of time getting the grade correct using a combination of spacers and a modified spirit level. This was all part of the build, check and test approach I used throughout the construction process.

I had to revise my exit arrangements from the spiral to the upper level of the layout. I had made a slight error in the measurement of the height difference between the upper and lower levels to the extent that the exit level had to be reduced from 5.3 turns to 5.1. The mis-close became obvious as I was setting out the fifth level and so the actual spiral finished around the 4.7 point and the remaining height is gained in the climb between the exit and the destination, the coal mine module. The photo to the right gives a birds eye view of the exit. The turnout will be the start of the Kingston Plains branch line.

As I was setting the height of each node, nuts were only finger tightened. I thought this would be sufficient but over the past few weeks, I have noticed some nuts required further tightening. I may have to revisit the whole structure with a spanner. 

Because of the long run of track in the helix (about 21m), I provided an electrical feed to each level of the spiral.

I used Peco track in the spiral and this track now includes provision for pinning on one side only. It's probably in literature somewhere suggesting that track should be pinned on the inside rather than outside of a curve. But I missed it and for ease of access, I pinned the outside of the curve. However, after a few days, the inner side of the track began to lift. I was able to correct this with staples pushed over the sleepers on the inside of the curve. See photos opposite.

Update

I had included a short Peco point (turnout) with a nominal radius of 650mm to provide access to the Mount Windeatt branch line. I hadn't noted any problems with the slight difference in radius between the helix (610mm) and the point when initially installed but over the past few weeks problems started to emerge particularly for the four driving axle steam locomotives. Maybe it was the changing climate or perhaps bumping the area during the adjoining bridge constructions, I just don't know. To overcome this, I increased the radius of the lower loop slightly where it joins the point and gradually transitioned this back to the nominal  radius over about half a lap of the helix. It was a bit of a pain to work on the lowest level of the helix with the upper levels in place, particularly having to insert a short additional length of track to facilitate the increase in radius. For me, the lesson is to keep points out of the helix.

And so the helix is now operational and the sequence below shows 4856's descent through the helix and exit onto the Yellow Rock module.

 

 

 

With the two levels of the layout now joined, attention has turned to the construction of the upper level staging area which represents Muswellbrook, Werris Creek and locations further north. With the helix  in place, I can also look forward to connecting the two branch lines, Mount Windeatt and Kingston Plains. These links will have to involve the creation of two lift up bridges, another challenging task. But it will give me the opportunity to run a few trains to actual destinations while I complete the rebuild of the Philip's Creek township.

 

Building a Helix - still joining the dots

I had intended that this post would detail progress on the Hunter River bridge, but the reality is that work on the bridge has stalled because my primary focus has been continuing to join the dots, specifically, building a helix. 

As I described in my most recent post, Philip's Creek, in its new arrangement, is now a two level layout and this means, I need some way to move trains from the lower to upper level and back again. To climb the 500mm between levels would require about 20m of track at a grade of 2.5%. Simply, there is not enough space in a 6m * 2.2m garage to run a visible climb between the two levels.  So there are not too many options other than a helix for continuous running between levels.

A helix is not without problems. A helix does occupy a lot of space. A 600mm radius helix will consume about 1.1m2 of space. This area may not seem to be a lot but when added to other space demands such circulation space and staging areas before we even contemplate sceniced areas of the layout. 

Access for cleaning and maintenance in the helix can be a challenge. Often I have seen a helix enclosed so trains are hidden from view as they monotonously go round in circles to gain height. However, this arrangement creates an issue if there is a derailment or when track cleaning is required. There have been horror stories of operators having to climb into the void at the centre of the helix to rectify a problem. I have decided to leave the helix open and accessible.

Another challenge is the combination of a tight curve and grade increasing the load more than it would for either individually. I have been very conscious of this problem and have experimented with likely combinations that will operate on the helix. To date, after being able to run up one and half laps of the helix, there have been no significant problems.

There are many documents and You Tube videos dealing with the design and construction of a helix. Most involve the cutting of circular sections which are then assembled into a helix. I was not too keen to do the necessary cutting of curved shapes and the associated wastage and I certainly didn't want to purchase one of the prefabricated kits available. I decided to try an octagon ring and lay a circular track within the limits of the ring. This has the advantage of simpler cutting of 10mm ply with less wastage. The strips do require some work with a mitre saw to cut each strip to get a 22.5 degree angle at the end. The eight section forming the octagon are screwed to short sections of 6mm ply which serve as a support or saddle at each the eight nodes. To support each level, I used 16 threaded rods, two at each nodes, with nuts and washers used to support each saddle. (see adjacent photo)

I struggled to fit the helix into the space available and had to reduce the radius to what I believe is the absolute minimum, 610mm. To accommodate this radius, the octagon had to have an overall width (A) of 1300mm and each side length (B) of 538.48mm, rounded up to 540mm.

To keep the grade to a reasonable value, I needed to restrict the height between helix levels to around 88mm with a clear distance of 70mm from track to the bottom of the next level. This gives a grade of around 2.3% and require about 5.5 laps.

The first octagon serves two purposes. It was the test bed for the construction process and once attached to the layout frame, it forms the foundation of the helix and the base for each of the threaded rods. 

One lesson which emerged from this exercise was the need for a slightly wider strip. Originally, I had anticipated using 100mm wide strips but I suspected this may be a bit narrow so increased the width to 125mm.

 The bottom circle of track had to include a point (turnout) which will connect to the Mount Windeatt branch line and the upper circle will incorporate a point leading to the Kingston Plains branch line.

With the first loop in place, I had to lay track from the Yellow Rock module to the helix and continue  into the helix proper. Getting into the helix  required the same tight radius but also a reverse curve. I incorporated a short straight in the hope that it would assist eight wheel steam locomotives to manage this section. Testing to date indicates that this arrangement has worked but it will be  speed restricted.

Once you finish one level of the helix, it is covered, and won't be easily accessible again. So the construction process has been a continual sequence of build/test. To date, I completed two loops with three plus to go.

Ian Millard (Liverpool Range) observed that one gets into a sequence or rhythm when building a helix. He's right! But Charlie from the You Tube channel Chadwick said that it's one of the most boring things he has done, and he's also right! Certainly, winding a nut along a threaded rod is a very mundane task, and it has to be done many times.

As I get closer to finishing the helix, I'll post again on a few lesson learnt but it's also time to contemplate the next projects, laying new track around Philip's Creek and installing lift up sections to access the branch lines. More to follow.