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Description : tail chaser around the garden on raised beds down either side with spanning bridges between the beds.

Controls: DCC with block detection using merg kits as well as Rocrail on a raspberry Pi for semi and autonomous operation

Distance: about 30 meters or about 2 scale km.

Material: Garden railway plastics from the usual supplier, peco trackwork

Regional bias: LNER however as always with elements of whatever i like.

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the viaduct

24 bricks make the viaduct for making a double track version with 2 bricks back to back, a full weekends cutting as i have a shoulder problem that slowed me right down.

fixed using compress expanding foam and ground stakes

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Edited by Damo2929
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nearing completion

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ok my skills not not great but it will do with just a bit of 60git to sand it flat

 

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just need to cut some keys stones now to complete a 50 mm gap in span 7 of the viaduct

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so far I have laid 10 yards of track and am experencing issues with expansion.

it seam that the plastic is expending pulling the track apart in the day and at night contracting causing the track to buckle 😒.

anybody have any advice on how to handle this with the plastic base ?

 

 

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Hi Damo, welcome to the forum, you must have expansion gaps between each length of flexi what  track are you using Peco is the best track for outside. I love the way you are building your decking same as me but all mine is module, I had a set back we moved before Christmas so a whole new layout design will keep an eye on your progress, I choose module because of the very hot summers we cop over here 

Love your viaduct we can't get those bricks over here same with the roofing felt, the beauty of a permanent layout you can build it quicker.

Tony from down  under 

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Hi Tony,

thanks for the welcome, I can imagine the aus temps can go way higher than here, I had a false start last year where I started building the track bed lower using deckboards then the mrs moved her bird feeder and steped on it and broke some of it so I decided that wasn't robust enough lifted it scrapped my cut corners and turned all the strights into planters. then moved on to building a cabin for a home office as I started a work from home job.

I came back to it this year and came across recycled plastic products which i snapped up but had to wait until after lock down and working hence why am building in late summer. I decided to add the decking to make beds simply to protect it and allow the mrs to plant round it.

with the track laying I did have expansion it's was about 1 to 1.5 mm ( creditcard width ) between each section when I laid it, however at night the gaps are closing, looking at it the plasitic base seams to shrink a lot over night where I have one track buckle then in the day when the plastic base is warming and expanding rapidly the gaps are opening to about 5 to 6 mm as the rails is not expanding at the same rate.

It's all the filcris track bed and am thinking I missed something when laying it, as it's expanding way more than I thought as I did leave that expansion gaps too but am thinking I maybe should have cut the 1.2meter straight board into smaller sections 300mm sections with 5 mm gaps to spread the expansion over move expansion points and as such not drag my track round as much. if anybody else has used this stuff it did you have simular issues ?

 

 

Edited by Damo2929
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I have heard that the Filcris plastic isnt much good - certainly not for our smaller scales.

I used recycled plastic sheet for trackbed and had a few problems with expansion / contraction, but generally only in one spot.

I cant remember the users name, but someone else on here used recycled plastic with, seemingly, better results - minffordd railway? Duncan suggested using shorter sections to minimise the effects in each piece, being careful not to pin the track near the board ends. I think he drilled holes in the sleepers, slightly too big for the pins - this gave the track room to move, without stressing it. Have a look for his layout thread.

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Thanks i have just gone though in depth, i see he used the same type of plastic in simular sizes however wood for the ladder while the deck left exposed, while i have used plastic which is quite dense as it is the 50mm pole cut in half, the two plastics have differing texture and density might be increasing the issue in my setup. I will run the circular saw though the plastic deck as based on Duncans specified rate mean smaller bit should only expand by a mm or so when at less than half meter. With it then expanding into the gap made by the saw the track might not see the movement.  I will then see what that does to the cycle over the weekend.

Edited by Damo2929
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well just cutting the bed didn't made a difference, I have noticed the issue is only on the straight sections as I laid a full curve and that is fine this morning, unlike the straight bit.

As Duncan didn't have this much trouble with the wooden ladder I can only assume it's the plastic ladder that's the causing it.

am just going to have to switch to Peco double and long set track on the straights which is a pitty since most of the track work is straight. mind you should speed up laying because will only need a pin or two per bit as the sleepers will be fixed.

just means I am going to have to move to dropper wires rather than using bonding wires.

 

Edited by Damo2929
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Hi Damo, no worries, yeah sure can get hot in summer, we a copping a hot test Tuesday 33 degrees can get hot in September. I have being lucky with the 12 mm ply I am using , modules are built pretty strong , plastics for base board what about track nails can you nail into the stuff,  pretty expensive over here , good for patios .

I haven't learnt how to put links  onto threads, I am working on an above arch bridge in Members Workbench  Aussietmrail  Modelling double deck cable stay bridges, the bridge I am modelling is just one level rail bridge, if you can't find it I will post the latest  bridge, construction is finished now , on your page.

Can't do anything in the shed for a week now, took the skin off just below the knee, ouch, will get stuck into  working on my model ship  in 1/78 scale  Ro, Ro ship .

Keep your progress pics flowing ,.

Tony from down under

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11 hours ago, Damo2929 said:

well just cutting the bed didn't made a difference, I have noticed the issue is only on the straight sections as I laid a full curve and that is fine this morning, unlike the straight bit.....

That must be so frustrating!

I've never used any type of plastic as a track base so my experiences with that material are none but I know how I was left feeling each time my timber bases began causing me grief. That's the reason why I eventually made the decision to relay my ground level exterior plywood sections with brick/blockwork. I'd had several years use out of the plywood so I couldn't complain too much but I just felt something more durable and permanent was required. The trouble is that bricks and blocks aren't suitable for everyone's needs.

I hope you're able to find a solution without it causing any further trouble.

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so the manufacture has come back with the expansion rate of plastic thay recommend for the ladder in the catalogue

2mm per 10degrees celcius per meter so the temp varience of 60 degress of -10 winter to 50 in direct sunlight

so on my 4.5 meter run that we are looking at thats 54 mm, and the other side is 9.5 meters that a 114 mm.

the advice from is to

Quote

place and remove track pieces in summer and winter

which is just unworkable.

am tempted to replace the ladder with with presure treated wood on the stright sections and just putting th plastic stright in the recycling but it's hard to  justify with it being £200 worth.

 

 

 

 

 

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You've made me think about expansion in my metal bridge plan but my thoughts might apply here too.

I was thinking about how real road bridges cope with expansion. The bridge sits on bearings that allow for the movement and then the surface has expansion joints. Could you split the construction into smaller lengths with the track only secured at a limited number of locations and have a sliding joint at the end of each section?

Basically allowing the plastic to expand and contract underneath without affecting the track.

Edit 7 hours later : Just so I understand the problem correctly.
I've looked on Filcris' garden railway page and can see a the contsruction method in some more detail.
You think the ladder section is doing the expanding and contracting, taking the top with it and the track cannot cope with the expansion and contraction rate of the plastic. If you were to do as Virginia Rail has done and take the top off and lay it on the ground, would the top on its own expand and contract and cause the same problem? If the top is expanding and contracting then you could try cutting it with provision for it to expand like my very rough diagram attached. I did note in your pictures above that you laid the plastic tops butted up against each other with no provision for expansion.

Is the ladder going to end up buried? If so then that may stabilise the temperature of the ladder section.

 

Damo2929 problem.jpg

Edited by Clay Mills Junction
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Hello Damo. I'm sorry to hear you have had trouble with your plastic track base expansion. I used a plastic base, laid straight on to earth, with Peco code 100 track. The plastic is called 'Foam PVC', supplied by Barkston in 5mm thick sheets. The base is configured in sections of about 1.5m, and the track is pinned to each section, with a track joint coinciding with each section joint. The longest straight runs are about 3m, so there is scope for the expansion of the base to be accommodated by moving on the ground. I have not had any trouble with track buckling, nor any significant problems with excessive gap at the track fishplates. I think allowing the track and base to move with thermal expansion is at least part of the reason.

I have been lucky! Have a look at my post earlier in the year under 'Virginia rail' if you are interested.

I hope you can solve your problems.

Kind regards

Peter

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Quote

Edit 7 hours later : Just so I understand the problem correctly.
I've looked on Filcris' garden railway page and can see a the contsruction method in some more detail.

Hi Clay Mills Junction, where can I find  Filcris garden railway page from couldn't find it on the net.

I am using 12 mm ply for my decking and  station modules, modular set up, most of my smaller sections and modules are 6 foot , have no problems with bowing and they are stored in a garden shed, can get very hot in summer , on those Aussie hot days I open the shed doors.

My longest section is the bridge  has a 14 foot main span in two 7 foot ply sections, took a while to build, need to clean up the top of the arch and  underneath before painting, double track , same with the curved sections no problems, still under construction taking a lot longer .

Tony from down under. 

 

 

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On 18/09/2020 at 13:40, Damo2929 said:

so far I have laid 10 yards of track and am experencing issues with expansion.

it seam that the plastic is expending pulling the track apart in the day and at night contracting causing the track to buckle 😒.

anybody have any advice on how to handle this with the plastic base ?

 

 

Do you use PVC foam as plastic base?

That's what I did, including a material called Forex.
And especially in the places that are exposed to a lot of the sun, this has not proven itself.
Dark colored plastic in particular has shrunk or deformed.
PVC rigid foam is probably not dimensionally stable if it heats up to over 60 ° Celsius.
And that happens very quickly in the sun.

I replaced the plastic with 6mm Medite Tricoya Extreme Durable MDF board in exposed areas.

And I also have a bridge with a beam made of aluminum profile and a support plate made of HPL.
Apparently HPL is also shrinking, because the base plate is now 1 cm shorter than the beam.

But that's only a visual problem because the rail profiles have not shrunk.

 

Pictures: 1 and 2: the mentioned bridge.

3: removed deformed Forex plastic base with pieces of slab track still on top...

 

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On 21/09/2020 at 11:47, Damo2929 said:

so the manufacture has come back with the expansion rate of plastic thay recommend for the ladder in the catalogue

2mm per 10degrees celcius per meter so the temp varience of 60 degress of -10 winter to 50 in direct sunlight

 

Calculating with 50 degrees in direct sunlight is not enough.
In direct sunlight, light-colored material reaches temperatures of over 60 degrees, dark material even in individual cases over 90 degrees.

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