Track Laying / Flexible Roadbed

jtilleyx

jtilleyx

Registered
17 Jun 2020
22
3
41
Pa
Hello everyone,

My loco (Piko Mogul 2-6-0), some starter track, and digital power have arrived. Ready to get started with initial layout.

I've been researching a lot of different methods and I think the HDPE Flexible Roadbed seems to best suit the area. I have found some 1x2 PVC boards for about $6 which seems pretty good considering other options.

Questions:
Anyone have experience with this method that can offer any advice?
If you have used this method, how did you handle sidings and turnouts?

Method
HDPE Flexible Roadbed - Part 1

PVC
 
GAP

GAP

G Scale Trains, HO Trains
14 Jun 2011
2,791
347
Bundaberg Queensland, Australia
Hello everyone,

My loco (Piko Mogul 2-6-0), some starter track, and digital power have arrived. Ready to get started with initial layout.

I've been researching a lot of different methods and I think the HDPE Flexible Roadbed seems to best suit the area. I have found some 1x2 PVC boards for about $6 which seems pretty good considering other options.

Questions:
Anyone have experience with this method that can offer any advice?
If you have used this method, how did you handle sidings and turnouts?

Method
HDPE Flexible Roadbed - Part 1

PVC
Is the layout going to be on the ground or elevated?
 
P

Paul M

Registered
25 Oct 2016
5,046
964
57
Royston
Is this the same as what we call Filcris over here? If so, you may need to thing about contraction/expansion. I use Filcris at groundlevel and don't seem to have any problems, but I believe there can be a problem on raised lines
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
17,506
1,977
72
St.Neots Cambridgeshire UK
Think it may be somewhat different to Filcris but not sure. What I do know is that Filcris does suffer quite severe expansion and contraction. The stuff refered to has this said aboutbit in the article.

“HDPE (high-density polyethelyne). HDPE is what you get from recycled two-liter bottles; it is chemically similar to the sheathing they use underlandfills, so it should be pretty stable. This "plastic lumber," also sometimes called "plastic wood,"“

I suspect linger experience of it will be the telling thing, though the article appears to be positive on stability.
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
27,682
1,672
North West Norfolk
In that case it's similar to filcris.

In theory, UPVC has a diabolically high rate of expansion. What it does in re-cycled form I don't know, even though I have a 20ft - 25ft section of slightly raised filcris track bed.

As with all things, if you've got a few curves in it, the expansion is taken up in the way the curves move. I've fixed my track at about every 18" on the filcris, and nothing seems to have moved too much, as in no train has fallen off the track :emo: - the odd post has settled a bit, but they're not concreted in - remember the whole railroad is built to Col Stephens' principles :p:p

So if a post settles, you just pull it up a pit, jiggle it around in the hole (for more dirt to fall to the bottom) and let it back down - you can do all this without dismantling track or filcris ladder :cool::cool::cool::cool:
 
Northsider

Northsider

Registered
3 May 2012
781
237
Both Filcris and the OP's material are HDPE (high density polyethylene), so comparisons with uPVC (which looks to have a lower thermal coefficient of expansion: Temperature Expansion Coefficients of Piping Materials) isn't necessarily relevant. The good news is, there must be plenty of modellers who have experience of using HDPE on both sides of the pond, and presumably not everyone ends in a horror story. I'm a thermalite block (with the occasional wooden 'bridge' still in place) kinda guy, so having (hopefully) cleared up any confusion of materials, I'll drop out of the conversation :).
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
27,682
1,672
North West Norfolk
Both Filcris and the OP's material are HDPE (high density polyethylene), so comparisons with uPVC (which looks to have a lower thermal coefficient of expansion: Temperature Expansion Coefficients of Piping Materials) isn't necessarily relevant. The good news is, there must be plenty of modellers who have experience of using HDPE on both sides of the pond, and presumably not everyone ends in a horror story. I'm a thermalite block (with the occasional wooden 'bridge' still in place) kinda guy, so having (hopefully) cleared up any confusion of materials, I'll drop out of the conversation :).
Nah, that's useful, 'cos to me plastic is just plastic :emo: :emo:
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
26,145
1,567
Tamworth, Staffs.
The first suggestions for using 'Filcris' (HDPE, as stated) were using flat sheets for the road-bed. - They would even cut this to the correct radius for LGB set-track curves.

It was found that it had a pretty vicious expansion-rate, and if the track was screwed down, then this could cause problems. - We get a (roughly) 40 C temperature range over the year (here in UK).

The 'ladder system' of supporting the deck (which you mount the track on) is not such a problem. - Yes, it will move a little, but a lot less than the top deck. The fact the supports are 'plastic', so will not rot, easily out-weighs the expansion problem.


The latest suggestion, is to use cut 'planks' across the support-ladder.. With a small gap between each piece (a couple of miilimetres, or so). Then each of these 'planks' will expand / contract a little, but the overall effect will be greatly reduced.
It is more work, and the material is not king to your saw-blades, but this seems to be the solution.

HTH?
PhilP.
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
17,506
1,977
72
St.Neots Cambridgeshire UK
The first suggestions for using 'Filcris' (HDPE, as stated) were using flat sheets for the road-bed. - They would even cut this to the correct radius for LGB set-track curves.

It was found that it had a pretty vicious expansion-rate, and if the track was screwed down, then this could cause problems. - We get a (roughly) 40 C temperature range over the year (here in UK).

The 'ladder system' of supporting the deck (which you mount the track on) is not such a problem. - Yes, it will move a little, but a lot less than the top deck. The fact the supports are 'plastic', so will not rot, easily out-weighs the expansion problem.


The latest suggestion, is to use cut 'planks' across the support-ladder.. With a small gap between each piece (a couple of miilimetres, or so). Then each of these 'planks' will expand / contract a little, but the overall effect will be greatly reduced.
It is more work, and the material is not king to your saw-blades, but this seems to be the solution.

HTH?
PhilP.
Another option is Eco Board, this is made from some kind of very small chopped plastic congealed or glued together. It comes in a gray colour 8x4 sheets and has fewer issues with expansion/contraction. Have used this on a friends layout on top of Filcris to get rid of all the issues with that stuff with good results.
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
27,682
1,672
North West Norfolk
The first suggestions for using 'Filcris' (HDPE, as stated) were using flat sheets for the road-bed. - They would even cut this to the correct radius for LGB set-track curves.

It was found that it had a pretty vicious expansion-rate, and if the track was screwed down, then this could cause problems. - We get a (roughly) 40 C temperature range over the year (here in UK).

The 'ladder system' of supporting the deck (which you mount the track on) is not such a problem. - Yes, it will move a little, but a lot less than the top deck. The fact the supports are 'plastic', so will not rot, easily out-weighs the expansion problem.


The latest suggestion, is to use cut 'planks' across the support-ladder.. With a small gap between each piece (a couple of miilimetres, or so). Then each of these 'planks' will expand / contract a little, but the overall effect will be greatly reduced.
It is more work, and the material is not king to your saw-blades, but this seems to be the solution.

HTH?
PhilP.
Ah, right gotcha.

Yebbut nobbut - the article that the OP referred to is just using the ladder prinicple - except, unlike filcris, you have to buy the stuff and cut it up yourself.
 
Last edited:
P

Paul M

Registered
25 Oct 2016
5,046
964
57
Royston
. - They would even cut this to the correct radius for LGB set-track curves.
But very expensive! I used 6" sections spaced a few millimetres apart around my curves, and use straight planks for the straights, seems to be alright, but mine is at ground level.
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
26,145
1,567
Tamworth, Staffs.
But very expensive! I used 6" sections spaced a few millimetres apart around my curves, and use straight planks for the straights, seems to be alright, but mine is at ground level.
I guess there would be a fair bit of waste? - Also, time, and cutters??

Unless you boards are in intimate contact with the soil, I do not think height will make a great deal of difference to the temperature the road-bed gets? - Colour, and any surface-treatment (light-coloured ballast, perhaps?) may make a bigger difference..
 
P

Paul M

Registered
25 Oct 2016
5,046
964
57
Royston
I guess there would be a fair bit of waste? - Also, time, and cutters??

Unless you boards are in intimate contact with the soil, I do not think height will make a great deal of difference to the temperature the road-bed gets? - Colour, and any surface-treatment (light-coloured ballast, perhaps?) may make a bigger difference..
no waste, but a lot of cutting. Mine is in intimate contact with the ground.
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
27,682
1,672
North West Norfolk
But very expensive! I used 6" sections spaced a few millimetres apart around my curves, and use straight planks for the straights, seems to be alright, but mine is at ground level.
MMm, can't help thinking, if you're at ground level, aren't there other simpler methods?

Or do they all have their drawbacks and you go with what suits you best?
 
R

rusty spike

Registered
4 Aug 2019
71
7
UK
My garden is in full sun all day and can get unbearably hot...I’m not a sun lover :-(
After posting questions and reading many articles on different sites, about the Filcris product, the cost and worry of buckling track bed led me back to my former building process. My fears may have been groundless but I couldn’t afford to take the chance. The delivery cost alone would have covered a third of my traditional building costs.
My previous layout was live steam and built on breeze blocks, concrete and the large spiral was treated timber on fence posts concreted in to the ground. I made sure all cut joints were re-treated and the whole lot was painted in two coats of Cuprinol Ducksback. When the line was lifted around 12-15 years later the wood was in tip top condition without any signs of rot or distortion. I don’t know if it helped the posts that we are on top of a chalk hill?
There are horror stories with the wood and plastic routes, but clearly either work for a lot of budding civil engineers !
Have fun,
Richard
 
JimmyB

JimmyB

Semi-Retired; more time for trains.
PhilP has talked about the 40C temperature difference in the UK, but that is air temperature (taken in the shade). If you material is in contact with the ground the ground will act as a heat sink, and will only be sightly above ground temperature, however if the material is above the ground and in direct sunlight it could easily be 20C above air temperature, making a significant difference.
As an aside I place an order with Filcris some weeks ago (after easing of lockdown), and it would seem it maybe some weeks till it is delivered.
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
27,682
1,672
North West Norfolk
Yup, well

Being a Retired Chartered Builder, I thought quite a lot about the cost and effort of having a railroad bed that wouldn't move. The answer is that it would probably cost somewhere as much as HS2 (foot for foot) and take about as long :p:p

So I went for Col. Stephen's prinicples - build it light and quick, 'cos the chances are it's going to move, and then it's not a lot of work to re-level, straighten it up, and get going again.

I've had to do a bit of re-levelling in a couple of places - one where a tree root has grown, and the other where a tree stump was ground up, and the line's settled.

There will be other places where it will settle, I can see one such that has moved a bit and is still OK, but if it moves any more, it'll be a couple of hours' work one winter afternoon and it'll be good for a few years again.

Suits me, sir :cool::cool::cool:
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
26,145
1,567
Tamworth, Staffs.
Are we allowed to drift yet? - Or shall I start a separate thread on laser-level's? :nerd::wondering:
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
27,682
1,672
North West Norfolk
Are we allowed to drift yet? - Or shall I start a separate thread on laser-level's? :nerd::wondering:
Not real drift when it comes to track laying - I surveyed my garden with a laser to determine the high point, and the other fixed height points, so that I could plan my gradients accordingly.

As gently on the accordion as possible :p:p:p
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
26,145
1,567
Tamworth, Staffs.
I think a separate thread?? - It can drift to other use(fu)less tools, and storage.. Especially lump-hammers! :):cry: