Garden Railway Forum

LNR wrote: ↑Mon Jan 22, 2018 12:46 am A 2018 Christmas Special then (dig, dig.).
You'll get there Andrew, and the result will be worth it. Remember this is a Hobby
meant to be for spare time, (can't believe I actually said that!)
Grant.

Yes, Life does tend to get in the way of important things like Railway Modelling sometimes....... Bloomin' nuisance.

Rik

Thanks guys, the encouragement does help. I'll get there, even if it does take a little longer than I planned.

Andrew

It's been far too long since my last update. The trouble is it's been far too long since I made any significant progress on the CFLR! The hot summer prevented me spending any time in the cellar - the current location for the S&C assembly yard! You'd think a cellar would be cool but ours is a very dry one that remains a constant 20ish degrees all year thanks to a dehumidifier gently humming away in the corner.

I DID manage to get a few more yards of track down. I had a turnout 99% complete when operations were packed away for Christmas, I got the tie bar fitted and that unlocked getting the additional track down as far as was possible before I reached the stage where further turnouts are required. That's the next big job. Two more and I'll have the ability to run on a continuous circuit. When that's done I need to start and think about the terminus station area, which will be the penultimate stage of the build. I also still have some significant civil engineering to do in the form of wall construction and concrete paving. That's on hold too at present.

I did manage one steam up over the summer to give the new track the 'acid' test - but that's been it so far.

The CFLR management examined the works recently and discovered that they may need to employ some pway staff to maintain the woks already constructed. The contractor undertaking construction has refused to deal with maintenance issues resulting from the delayed pace of construction. This takes the form of vegetation incursion and work is going to be needed very soon to deal with this. Management are considering careful removal of undergrowth to use as planting material on newer parts of the works. The pictures will explain.....

Thymes are beautiful plants and very much in scale - but they creep! The loop points have suffered at Woodhouse too Somewhere beyond this is a tunnel! And if you think thymes are invasive don't mention the lavender! Hopefully I shall be posting further updates in the future and at shorter intervals than seven months!

Andrew

Welcome back Andrew, interesting to see how the plants have settled in, the line will look well established before its finished!

On my recent trip aboard the Sittingbourne and Kemsley, the driver slowed down a couple of times so the fireman could attack the buddleia and brambles which were growing out over the line at head height. Seems we're not the only ones with plant problems .....
.
Maybe one of us should set up a nursery selling railway friendly plants - I think it would be a goer!

Rik

ge_rik wrote: ↑Thu Aug 30, 2018 8:31 am
.
Maybe one of us should set up a nursery selling railway friendly plants - I think it would be a goer!

There used to be a garden centre down near the Kent & East Sussex Railway that did that. They had a railway running through the plant displays and I think did open days, but although the garden centre is still there the railway side of it seems to have disappeared.

philipy wrote: ↑Thu Aug 30, 2018 9:02 am There used to be a garden centre down near the Kent & East Sussex Railway that did that. They had a railway running through the plant displays and I think did open days, but although the garden centre is still there the railway side of it seems to have disappeared.

It was a visit to Bodiam Nursery in 2013 that got me into this whole 16mm-in-the-garden-thing. They've got a lot to answer for!

The garden aspect of the hobby can be every bit as much enjoyable as the railway for me. I get every bit as much pleasure from seeing the railway winding it's way through the landscape as I do from seeing a train run on it, possibly more so! This hobby is nothing if not varied.

Andrew

Hello Folks,

It's been a long time since I last provided an update on the CFLR. The fact of the matter is that there has been nothing to report! Circumstances have dictated that priorities be directed elsewhere and I don't think I ran a single train last year. Not only that but there was no progress on track construction either. The only think I DID manage to do was to put finalise the cross levels and alignment. A few weeks ago I was doing some tidying up in the garden when i noticed what looked like a buckle in the end of a curve. It's hardly been the weather for that! Closer inspection revealed at least two other places where this had happened. Two were on embankments but the third was on level ground and I fancy there is a fourth in a shallow cutting. The track is pinned with 6mm brass pins into Filcris runners, supported on 18" Filcris posts, all buried in the ground up to the top of the Filcris. I thought it might have been movement of the Filcris but it stood the heat of last summer without a twitch, so why it would move in the cold of Winter I couldn't understand. In any case, there was no sign of movement in the ground around these areas, so I'm at a loss to understand what's going on. With no immediate prospect of continuing construction, thus making running any train even less likely, I think I shall leave things as they are and see what happens. If there is any change I'll provide an update.

The original problem site. The two other sites discovered at the same time. Sorry the pictures are on their side, I tried turning them but failed miserably. For the purposes of illustrating the alignment fault though they do the job in any orientation.

All the best,

Andrew

That's very strange have you tryed running a train over it .if you do and it's fine I would leave it as it is

That is decidedly odd. The first thing I would have fingered is the Filcris because it is known to have a high degree of expansion and contraction. However, I would have expected it to go bananas in the summer not now. Any idea what the temperatures were when you laid first the Filcris and then the track? How far between expansion joints in both materials? It looks like the filcris had contracted more than the track, but that is just my gut reaction to the photos.

Cheers,
Peter in Va

Two thoughts pop into my head.
1) what is your soil, or possibly sub-soil if its been terraformed? My clay causes inexorable movement in all three planes, but even gravel types soils could be prone to settlement, and hence sideways movement, over a wet period.
2) It might be worth checking in UNdistorted areas in case the rail has crept. i.e expanded when it was hot but the contracted unevenly, and repeated. So you end up with largish gaps in some areas and distortion in others.

Just thoughts, I don't actually know.

It looks similar to the problem that I had when using Filcris, I didn't leave enough of an expansion gap in my rails which was Peco incidentally. During hot summer months the Filcris expands far more than the track but in the cold months it contracts far more than the track, leading to the expansion gaps in the rail closing up and the inevitable happening. I solved my problem by increasing the rail gaps to around 4 - 5mm, I know it doesn't look very prototypical but it does stop the track distortion.

Thanks for the replies folks. There are some interesting points of view, I knew I could rely on you!

The Filcris was built in quite a warm period but not fully buried until cooler weather. The track went down in some fairly warm weather (but after the ground had been built up around the Filcris), so the suggestion of it being due to differential expansion and contraction is the most likely one in my opinion. Our soil is a a sand gravel mix and generally pretty stable. It's the differential expansion and contraction that's most likely done it. I should have thought of it myself as it was one of the considerations I included when deciding on the type and construction of the foundation. Based on other experience gained off this excellent forum I concluded that burying the plastic would prevent any problems. The embankments have shrunk away somewhat since construction, about 1/2" to 1", but it's old settlement and now stable. This may have allowed a little bit extra movement of the Filcris at the end of last summer.

I'm in no imminent danger of running any trains (even if I did, I think the alignment is passable) so I'm going to leave well alone for now and see what happens. If action does prove to be necessary then I think increasing the size or number (or both!) of expansion joints will be the way forward.

I'll report back later in the year.

Andrew

Soar Valley Light wrote: ↑Sun Mar 17, 2019 1:47 pm so the suggestion of it being due to differential expansion and contraction is the most likely one in my opinion.

It seems to be the most likely cause. Out of curiosity I looked at the coefficients of linear expansion for plastics and metals and did some back of the envelope calculations......

Filcris say that their product is mostly HDPE (Polyethylene) which is quoted as approx. 110 microns per metre per degC.

Nickel silver (rail) is quoted as approx. 16 microns per metre per degC.


I used my backyard as a worked example. It has an air temp range over the year of 40degC and surface temperatures can get over 50degC on cloudless days. So if I'd used recycled plastic, every metre of framing would change length by around 5mm between a winters night and a summers afternoon. Eeeek.....

My rail is brass with a co-efficient of 18 microns per metre per degC, so every metre of rail will only change length by about 1mm over the year.

The expansion amount will vary in a different climate, but the 7:1 ratio in thermal expansion won't change. Installing Sisalation sheeting between the ballast and the Filcris structure might insulate it enough to reduce the amount of thermal expansion/contraction relative to the rail over the year.


I think I dodged a bullet, as I was contemplating using recycled plastic early in the design phase, but eventually decided on steel framing for the raised structure.

Regards,
Graeme

Interesting stuff. I'm tempted to use breeze blocks for my railway when (if) I get a round tuit. I did consider filcris or recycled plastics for durability. I guess the solution is to leave plenty of large expansion gaps if expansion and contraction proves to be the issue?

What a fascinating hobby this is. Here we are discussing the finer points of thermodynamics in relation to materials. We should get garden railway modelling on the school curriculum and as a post graduate degree syllabus.

Rik

ge_rik wrote: ↑Mon Mar 18, 2019 12:40 pm What a fascinating hobby this is. Here we are discussing the finer points of thermodynamics in relation to materials. We should get garden railway modelling on the school curriculum and as a post graduate degree syllabus.

Rik

I like that Idea Rik. For the first time in my life, I would stand a half chance of getting a degree!

Following up on Graeme's very interesting information (Thanks Graeme) - I thought that using a geotextile over the top of the Filcris and burying it up to the top might keep the temperature of the plastic down, and so reduce the greater expansion and contraction - not that I ever dreamt that it would be such a large movement! I'm still hopeful that this may work, I just need to get the sunken areas built back up. The other thing I'm hoping will mitigate this movement is established flora growing on the lineside. It's noticeable that the movement has occurred where vegetation is at it's most sparse coverage. This spring should see the plants really establish themselves so I shall watch what happens during the coming summer with the greatest of interest!

Out of interest, I tried to reduce the risk of erosion on the embankment slopes by placing large grantite blocks (standard gauge ballast!) as edging blocks on the outside of the cess. I reckoned without the civil engineering aptitude demonstrated by our local Jackdaw population though! In their search for food they flick these not insignificant lumps of stone over (and down the slope) without the least effort! They are great entertainment but completely unmanageable. I enjoy their presence so I think I shall have to resort to some cement to fix the stone blocks together in sections big enough to defeat my feathered friends.

Andrew

Soar Valley Light wrote: ↑Mon Mar 18, 2019 8:01 pm - not that I ever dreamt that it would be such a large movement!

Surprised me as well. Then I noticed pandsrowe had reported similar results.

What surprised me more was that I remembered how to do the calculations, as it's getting on for 50 yrs since I studied thermodynamics...........

Soar Valley Light wrote: ↑Mon Mar 18, 2019 8:01 pm It's noticeable that the movement has occurred where vegetation is at it's most sparse coverage.

Wouldn't surprise me if getting a good covering of soil and foliage over the Filcris improved things. Moist soil shaded by plants should maintain a more stable temperature.

Regards,
Graeme

hello, sorry to nose in, but I wanted to ask about the Filcriss?

How is it going now?
.
I'm looking to use it as a temporary structure, so the expansion/contraction differential highlighted shouldn't be such a problem.

Looks a lovely railway

Thanks

Mike