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ba14eagle

Hampton Field Railway - Overview of construction

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When my wife and I moved to our house in 1998, construction of a garden railway was high on my list of priorities (as well as all the usual decorating etc). I was allowed an area of the back garden which was situated along one whole side of the pathway, measuring approx 6 ft wide (I know - not much for what was going to be O gauge!) x approx 60 ft long. The garden here was a bit of a jungle, with a number of large well established bushes & shrubs. :shock: avid gardeners look away now :!: These had to go - I do like plants and shrubs, but I don't like huge. Ground cleared, a rendered blockwork retaining wall was built around the site with adequate drain pipes at the lower end. With the slope of the garden over its length, this created a raised bed, which was a block high at the far end of the garden and 3 blocks high at the house end (This is the only thing I don't like about the railway now - its a bit too high and 'hard' on the eye - should have made it a block lower all the way round. ahh hindsight!) Before I could then start building the trackbed I had to do plenty of filling - mostly recycled railway ballast from our nearby depot at Westbury. With the level I required achieved, I started on the trackbed.

Very early on in the project I had bought a second hand, electric builders concrete mixer. This had plenty of use and was a godsend. When I'd finished with it, I sold it on - at very little loss too. Concrete was poured into shuttering, which was constructed from hardboard sides with attached wooden stakes (could have done with more stakes - the weight of the concrete moved the shuttering a little). The shuttering was filled to within a couple of inches of the top. When the concrete was set, the 'rubbercrete' track base was used to fill up to the top. 'Rubbercrete', as it is known, featured in the construction of a garden railway in an early edition of "ModelRail" magazine. It is a mix of cement, granulated rubber, chipped cork, water and external grade pva glue. It sets hard but will take track pins by virtue of the cork and rubber content. Due to cost and the logistics of getting the chipped cork (I had already gone all the way to Northamptonshire to get the granulated rubber), I replaced this with gardeners vermiculite - cheap in comparison and very easy to get from garden centres and the high st. Once set, this is sealed with a wash of water / pva mix. If you wanted to, I suppose you could push the boat out and use a commercial brickwork / rendering sealer - you know the one! The attached photo shows part of the trackbed after completion - the construction technique can be easily seen. The Helipad is now in the loop of the 2 parts of trackbed seen (see photo of 4F hauled train in other forum). After the trackbed was completed all round, the gaps were filled with topsoil and planting out started. There are also a few concrete slabs set on blocks, throughout the planted area, where buildings and cameo scenes are situated.

After looking at the photo and thinking about how it was all done, I realise that the railway is far too over engineered and was built at a cost which was too high. I don't envy anyone who wanted to demolish it! Should I build another somewhere else, I would put a lot more time and thought into planning the construction so this didnt happen again, but as they say, that's the benefit of experience for you. I am still not a huge fan of wooden trackbases outside so would seriously consider using Mick's technique of using blocks laid end to end, but with the addition of a 'rubbercrete' trackbed on top.

HFMR construction 1.jpg

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I've heard/read about 'rubbercrete' in several forums/articles before but I'm still unsure exactly what it is and how you get hold of it. Do you have to purchase the ingredients separately? I'm beginning to think that it's not something I can get hold of in handy sized bags from the local DIY store :?

Personally I've been quite happy with my decking board base atop the building blocks but like almost everything I've done to date, I just wish I had taken more care with the block laying and got them absolutely level. I've fastened the decking boards down and they follow the level of the blocks which I could have made a much better job of in some sections. Where I have managed to get the blocks something like level, the wooden track base is exactly as it was the day I fastened it all together.

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Mick

You're right! If only something akin to rubbercrete came in a handy bag from your local builders merchants.

Ingredients are : Cement, granulated rubber and cork, water & pva / sbr. Cement, water and pva/sbr are obviously easy to lay your hands on, but the rubber and cork are a bit trickier. As I mentioned, my rubber granules came from a tyre recyclers in Rushden, Northants (I am pleased I had the foresight to buy a good deal of it, as I still have enough left for what I need now). I couldnt :x get cork too easily - I think the nearest supplier at the time was in Manchester and it was expensive - so I used the vermiculite instead. I'm having similar problems now trying to get granulated cork (even the internet doesnt throw up too many suppliers in the UK), but have discovered that particular types of fisherman use it as part of their bait, so I will now be going to my local fishing shops to see if they have it in the right quantities I want - and price!

I will take some more photos of the mixing and application of it when i'm at that stage and post them here.

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Look forward to seeing photos and description of the 'rubbercrete' application in due course Iain. Spent a few minutes with the aid of Google searching for granulated rubber around my locality but not yet come across anything positive as a possible source although even if I had I'm not sure I would be in a position to do anything about it just yet. It's something to think about for next time perhaps.

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When it comes to track base construction for a garden level line has anyone considered using Thermalite blocks as they take track pins if your careful in hammering them in and although they're supposed to be rendered you could render just the side and then lay some of your roofing felt over the top, or lay the track work and using a mixture of quick drying cement and ballast to do the top that way. We have the English company Hanson's here but they don't do Thermalite blocks as they don't consider it to be part of their core business, or so they told me in an email. I thought they were in concrete products not apples.

Over here we have a European product called Hebel which is similar although pure white in colour. You can't use ordinary cement with it either you have to use the special Hebel adhesive which is very expensive.

Roy.

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Hurrah :!::) Drier, warmer weather has finally reached Wiltshire and I managed to venture outside on Sunday and do some work on the HFRv3 trackbed.

In the picture at the top of this thread, on the extreme right, there is a narrow section of trackbed, which although good enough for single track in O and G scales, isnt wide enough for double track in OO. So this is to be the worksite for today. I had previously dug out some of the earth and planting from behind the trackbed at this point and laid some concrete in the void. All I had to do now was to lay some "rubbercrete". Upon further inspection I decided to also dig out some more earth, so as to be able to ease out the curves at this end of the line. Below, hopefully attached, are some shots of what I did.

Picture 1 & 2 show the various ingredients of the "rubbercrete" mixture. Pic 1 shows the granulated rubber, Pic 2 shows on the left the 50/50 water/builders pva mix, whilst on the right, is the cement dust now added to the rubber granules. All these elements were mixed together to a slightly running consistency before I moved over to the worksite. Pic 3 shows the worksite, with the previously laid concrete and extra digging in evidence. The "rubbercrete" was laid into the void and smoothed out with a dampend plasterers float. the completed job is seen in Pic 4. The area was then covered with sheeting, to allow the mix to cure / harden. Depending on how smooth this turns out to be, I may add some very fine cork granules to the slurry of cement, water and pva which is to be brushed on to seal the surface.

Picture 1.jpg

Picture 2.jpg

Picture 3.jpg

Picture 4.jpg

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Very interesting, please keep us updated on your progress.

Ian.

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Ian's right, this does look very interesting and I would imagine that further combined with the 'snap it' garden edging system referenced in this same section of the forum, it could prove to be the answer to many outdoor modellers dreams.

Once constructed is the fully cured base rigid or slightly flexible? It can obviously accept track fixing pins but do they hold securely? Is the mixture strong enough to be used in other applications such as building 'a viduct'? Yeah, something lighter weight that could be moved around or removed easily might be a better idea for me!

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Mick

I have not had any problems with track pins whilst the line had larger scale track - I was lucky, as you could use heavier duty pins (obviously not steel ones!). The track remained firmly pinned down and still. The only problem I didnt foresee :o when it was version 2, with plastic track, was that the plastic expanded in the heat and it rose up to a peak! I tackled this by sawing off a little tiny bit of the rail and the moulded fishplates at 2 or 3 points around the circuit, to create some expansion gaps. I am intrigued to see, if when laying the oo peco streamline, if small pins will go into the rubbercrete, or whether I will be bending more than I actually use :!:

With a good mould, I dont see why you couldnt use rubbercrete to build your new viaduct, although I would use a small amount of real concrete to foot the supporting pillars.

Iain

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HamptonFieldRailway said:

...I am intrigued to see, if when laying the oo peco streamline, if small pins will go into the rubbercrete, or whether I will be bending more than I actually use :!...:

I had problems with the thinner trackpins bending while I was fixing the track down in the shed onto a plywood base. The odd ones went in okay but the vast majority of them folded unless I gave them several short gentle taps rather than a blow with a heavier hand. In the end I purchased some thicker pins that are claimed to penetrate plywood but I've not tried them out just yet.

HamptonFieldRailway said:

...With a good mould, I dont see why you couldnt use rubbercrete to build your new viaduct, although I would use a small amount of real concrete to foot the supporting pillars.

Iain

I was just curious as to the finished strength of the rubbercrete mix. I would imagine that there are a number of similar products to ground rubber granules that could be used instead of sand/ballast to make a less heavy casting. Concrete is so permanent and a fully completed viaduct would be immovable once it had been cast. Something that could be moved around, or perhaps even taken with you if you moved, but that was also stable in use would be ideal.

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In response to a request, by PM, for the rubbercrete recipe, here it is. This is the original Trevor Jones recipe, which I deviated from very slightly (you will notice this if you read all of this thread).

I will show volume as "parts". I used a small plastic pudding dish as my measure for 1 part - the sort of thing that a microwaveable sponge / christmas pudding comes in! The article containing all the information is in Model Rail magazine Autumn 1998, if you can find a copy...

2 parts rubber chips

6 parts of cork chips - 2 each of fine, medium & coarse (or vermiculite in my case)

4 parts cement

3 parts water & 1 part sbr / adhesive mixed.

Trevor Jones advises

Quote

a medium sized yogurt container should provide you with roughly the correct quantity for a 6ft by 4.25" section

* this is based on a depth of .5" - .75" *

Mix all the dry componants together first before adding the liquid. I added liquid or dry mix to adjust the consistency as I was happy working with, but avoided making it too wet in case it shrunk and cracked as it dried. Once it has thoroughly dried, you can smooth the surface (if required) with a surform, before sealing with a slurry mix, applied with an old paint brush. The slurry is a mix of water, cement and SBR / adhesive. If you have a few cracks in your rubbercrete, you could add some of the finest cork granules to this mix. TJ also recommends adding a black mortar colouring to it. Sorry, but there are no precise quantities quoted for this slurry - it was just trial and error!!

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Looking at videos, the rubbercrete tracks, yours (Hampton Feild Railway) and great wakering (trevor jones) - the rubbercrete track base looks such a good surface both in realism and in practicality.

Thankyou for including the recipe, hope to try it this early next year.

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It seems s few of us have had problems over winter with the wooden track bases and while my own problems are relatively minor I know it's only a matter of time before I have to renew the section of plywood track base spanning the section between my two viaducts. I'm ashamed to now find myself looking at the 'rubbercrete' method as a replacement and asking unnecessary questions when Iain has already provided most of the answers in this thread. I had even completely overlooked the fact that I've already participated in this topic and forgotten all about it. I am now almost certain that I will be using the 'rubbercrete' method to replace my ground level plywood bases. That may be some time this coming summer or I may decide to leave it until absolutely necessary but I would like to feel that next winter I will be able to sit back and not be unduly concerned about the effects of the weather on the layout.

I think we need a fully detailed article on the use of 'rubbercrete' as a track base.

Iain, can I ask how you went about your attempts to lay the rubbercrete level? Is it easy enough to apply and does it work easily? Can it be levelled/sanded once it has dried?

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Interested in your use of vermiculite as a substitute for cork chips. I've got a couple of large bags of cat litter sitting in my greenhouse (as you do when you don't even have a cat!) It was purchased with the intention of using it as a filtration medium for the pond as it doesn't break down in water. I'm wondering if that would suffice as it's very similar to vermiculite?

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Mick

I left the shuttering in place from the concrete trackbed construction and, having filled that to within an inch of the top, i then topped it up with rubbercrete. It was all very hamfisted, as the photo at the start of this thread shows, but it has worked and has been very durable - almost indestructible :lol: . Next time, I would look at using that plastic garden troughing stuff that electric fox has used, or shuttering again, but something a little stiffer, as the hardboard did move quite a bit! This allows you to run a plasterers skim thingy along the top of the shuttering, to get it flat / smooth.

Yes, it can be fettled with a surform. This was one process though that was made more difficult by using coarse vermiculite, rather than the cork granules, as the surform caught on the edge of the vermiculite and spoiled the nice flat surface (At the time it didnt matter too much as I was laying O gauge track, not OO). In future I would use cork granules or dust, instead of vermiculite - It was only an idea that I tried in order to reduce the costs of construction. At the time, there were few places to buy granulated cork and it wasnt cheap.

The rubber chips came from recycled tyres - a company in Rushden, Northants. Large bags were about a tenner each. Cannot remember the name of the company im afraid :|

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My problem with the Rubbercrete method (as I mentioned on Mick's Worsley Dale thread) is that I cannot now use shuttering because the trackbase is already in situ and is either on a low brick wall or at ground level between rockery sections, effectively in a cutting.

There is another section that would have rockery on one side and lower level rockery on the other.

If I was to glue battens across each end of sections, would the Rubbercrete mix be firm enough to be "tamped" down and not fall away before it had set? I am thinking the shoulders would need to be rounded off, on the sections where the trackbed is higher than the surrounding area.

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Riddles

Unfortunately, this method is only really suited to a new construction. However, where you are on a brick wall, if its not too wide, could you not use (G) clamps over the top, to hold some shuttering in place?

And in a cutting, can you not drive some shuttering in a little way, to keep it rigid? You really must have something to keep it in place, whilst it dries, or you will never get it level.

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Thank you for that. It is much better being able to ask someone who has used the stuff, and knows how it handles.

Unfortunately my trackbed is by no means straight. I think dead straight track looks a bit toy like and unnatural although I do like the idea of using concrete fence posts where no curves are possible. What I am now thinking of doing is gluing wooden battens (18mm x 28mm) wide side down, at the edges of the formation, to create mini-shuttering. These could be cut in shortish sections to follow the curves and I would try fixing them with Gorilla Glue which seems to have a good reputation.

Do you think 18mm is deep enough and would you paint the existing concrete/brick work with some sort of sealant first? Or, do you think it would stick to the base without any problems? How long does it take to set hard on a good day? I might remove the battens after it had set and put a 45 degree slope of Rubbercrete in their place. Or I might just leave it to rot naturally.

A lot of questions I'm afraid but I do appreciate your help.

P.S. I've just read Mick's mention of Gripfill on the New Railway thread. That would probably be more cost effective than Gorilla Glue.

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Riddles

I dont see why you would need to treat the base first, unless you were using blocks that could be affected by damp.

Mini - shuttering will work, secured as you suggest. 18mm should be ample depth. Obviously, try and get the tops level :)

I wouldnt be too hasty in trying to take the shuttering off - I treated mine just as though I was laying concrete. Cover it with something whilst it cures and give it a couple of days - weather / temperature depending ;) You can angle off the edges with a rasp / sureform when its solid, but be a bit gentle!

I know this all seems a bit of a faff, but believe me, mine is solid as a rock, over 10 years on, but with the advantage of being able to pins in it!

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That's the way I'll go then, when the weather gets better. Thanks for all your help.

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