Spirals

Home

This shows where the layout will live. It was drawn using Templot.

We have the garage, the laundry room and the back room. The front room is adjacent to the garage and used to be the other half of a double garage. All the rooms are garage width at 8ft.

To the right we have Swanage at the top level in my back room.

To the left is the outline of the hidden sidings boards in the garage on the bottom level. The are described here

The single track from the hidden sidings runs through the laundry room and into the back room at the bottom level.

The spiral is at the end of the back room under Swanage.

Most of the visible layout lives in the garage.

The main line from the spiral runs through Hamworthy Junction round and back to the spiral.

The Old Road leaves the main line in the back room and rejoins it at Hamworthy Junction.

The Hamworthy branch leaves the junction and runs into Hamworthy in the front room next to the garage.

Having run around the spiral about 7 times the main line from Hamworthy Junction emerges through Wareham which extends from the middle of the back room, through the laundry room and into the garage above Hamworthy Junction. It then follows follows a circuitous route to Worgret Junction in fthe front of the garage.

The main line then returns to the spiral and goes all the way down and back to the hidden sidings.

The Swanage branch leaves the main line at Worgret Junction running through Furzebrook and then runs around its own spiral about 7 times.

The branch leaves the spiral and runs through Eldons siding against the garage wall rouind and through Corfe Castle which is above Hamworthy Junction before running into Swanage.

I should say that although this is presented in the present most of it belongs in the future.

Templot assures me all the stations will fit at scale length.

The Spiral

Originally I planned for a double track spiral with junctions out and back to each level. That would have been a real headache to access the junctions for maintenance and operation would be complicated. Then I realised that with a four track spiral I wouldn't need any junctions on the spiral at all. So here is that plan.

The single track from the laundry room and hidden sidings enters the back room from the left. The layout for the loco depot is based on Bournemouth Central but that plan is still under development.

The single track opens into four tracks. The two at the top run all the way up the inside of the spiral. This is the double track on the Weymouth side of Wareham.

The other double track is the main line to Hamworthy Junction which will be located in the garage to the left. This will split before entering the laundry room to become the main line from Poole and the single track old road from Broadstone.

It was suggested that I might have a problem with runaways. I decided that the prototype solution to that problem was to include enough of the track approaching the spiral in the block containing the spiral to allow a runaway to safely come to a stand. That allows an optimisation of the amount of track needed for the spiral. The double track from the bottom level to the first level will now be single and open into the two track main line and the Old Road at level 1. The double track running down the inside will now merge into one before entering the spiral and so the innermost track will not be required. I will leave the spiral construction as is in case I change my mind later.

My grand plan also requires a single track spiral for the Swanage branch.

Some research and development is required to verify that scale length trains can negotiate the curvature and gradient of these spirals.

TrainBrain Layout Diagram

This is the layout diagram from TrainBrain which is the software I will use to control the layout.

At the bottom we have the single track from the hidden sidings which splits into two and approaches the spiral. The RHS represents the spiral.

One track goes up one level and splits into three. Two of these form the main line through Hamworthy Junction. The other is the Old Road, also known as Castlemans Corkscrew, through Ringwood, Wimborne and Broadstone joining the main line again at Hamworthy Junction.

The main line then returns to the spiral and continues up many levels to Wareham.

The Swanage Branch leaves the main line at Worgret Junction, through Furzebrook, up a second spiral above the first, past Eldons siding, through Corfe Castle and then on to Swanage.

The main line from Worgret Junction reduces to a single track and runs all the way down the lower spiral finishing back at the hidden sidings.

Back Room

This is the back room. The mess is my excuse for work in progress. It is 8ft wide, the same as the garage, and 17ft long.

The single track from the garage comes in along the left hand wall. My O gauge is underneath and runs down the room and through the window wall into the garden.

My work bench is on the RHS.

I call the middle of my spiral my play pen and it was where my 3D printer lives. I have now moved it into the front room.

The single track from the hidden sidings splits into two and then runs into the spiral about half way down the room. Both tracks run up to the next level where the outer track comes off the spiral and splits into three about where you can see my spirit level. Two of these tracks form the main line and the other is the Old Road. All three tracks run back through the laundry room and into Hamworthy Junction in the garage.

The main line runs around the garage, over the hidden sidings and back to the spiral above the spirit level. This continues around the spiral up to Wareham which starts above the spirit level at about the height indicated by the support and continues through the laundry room and into the garage.

Eventually the main line reappears one level up, reduces to a single track, runs over the double track to Wareham and then all the way back down the inside of the spiral to join the single track from the hidden sidings at the bottom level.

As well as the double track from Worgret Junction and Wareham the single track branch appears on the left and runs up a second spiral back around the garage to finish up in Swanage along the left hand wall.

I hope that is all clear!

Spiral

This is a closer view of the spiral.

Level 1, by the orange pliers, is the entry from the hidden sidings. Level 2 is the exit to Hamworthy Junction here and the return is at level 3 above the current board.

The 1 metre M6 screwed rods are more than long enough to reach the top level which will be Swanage.

Construction

So let’s take a closer look at the construction.

The track bed is 6mm MDF from B&Q. It is wide enough for 4 tracks although the current design only requires 3. Templot templates are stuck to the top with a spray adhesive and the underside is sealed with MDF sealer and painted with a mould resistant white paint.

The spiral is divided into 4 quadrants. I can cut the 4 pieces for one level from 1 sheet of 8’ x 4’. B&Q cut 2” off one side and then down the middle giving me 2 x 48” x 46” which will fit in the car.

The middle 2 tracks are at 50mm centres and the outer tracks at 36mm. The radius of the inner track is 36”.

The gradient is about 1 in 100 which is enough to give a minimum clearance between levels in one circuit. The feet and spacers are 3D printed as we will see later.

The spacers mean that once the bottom layer is adjusted correctly all the other levels automatically align. There will be 1 nut under the bottom layer and another above the top layer. Once tight this makes the whole structure very rigid.

I am glad I hit on the idea of using the spacers since assembly with individual nuts for each layer would have been a nightmare.

Feet

So lets take a closer look at the components.

I 3D printed the feet for the screwed rod. They are fitted to the rod with nuts and washers inside and out. The feet just sit on table tops. Up to now I have used nyloc nuts inside the feet but nowhere else. Since I am now only using 4 nuts per rod I think I will use nyloc nuts throughout.

Spacers

I also 3D printed the spacers. They are all the same length ensuring a consistent gap between levels.

Board Joiner – in situ

After much refinement to hold the rail firmly but allow it to slide freely I managed to 3D print board joiners and rail joiners.

The track on each quadrant is just under 6ft long so there are board joiners at each end and a rail joiner in the middle.

The board joiners are aligned using finescale rail which also acts as a check rail.

3D printed straps hold the boards together with M3 hex headed bolts passing through the strap, joiner and MDF.

Boards can be removed by sliding out the check rails and removing the bolts and straps.

Board Joiners - components

These are the components for the board joiners.

The board join runs down between the bolts.

The tracks are numbered 1 to 4.

The board ends are printed in 2 “halves” because my printer is not big enough to print them in one piece.

The track rails are curved to match the radius of the spiral tracks.

The check rails are curved more sharply but not flared so that they can be removed easily.

The check rails also serve to hold the joiners in alignment.

There are 3 straps to hold the join together.

In the previous picture the bolt heads are shown embedded in the straps but I have just about decided it is better to embed the nuts in the strap and add the bolt from underneath as shown here. This makes it easier to remove and install them in what is a very restricted space when the MDF boards are in place above and below.

The curved pieces are track “settas”, one for each track at the correct radius. They include 2 ridges which fit between the check rail and the running rail. They help to maintain the correct alignment from joiner to plain track.

Rail Joiners

The rail joiners hold the rails in alignment and also provide the means for electrical feeds.

These are similar to the old Triang ones with a piece of bent phosphor bronze strip and the wires soldered to PCB strips. These slide under the rails in the gaps provided by the joiners.

The sleeper base is stuck down to the paper templates using PVA but the joiners are not fixed.

It has been a bit of a nightmare finding the right dimensions to hold the rail firmly but allow it to slide through the joiners.

Yard lengths of rail can be removed and reinstalled through the board and rail joiners if required once the sleepers have been glued.

Proving

My plan is to install the first 3 levels allowing me to run from the hidden sidings through Hamworthy Junction and back. Then I need to prove that my stock will handle the spiral.

I am building a test train using some old Kitmaster coaches and a Triang MN converted to 14.2 but that is another story.