To Ballast or not to Ballast

[Andrew_au]

Currently, I have 3 different types of base on my railroad:

• Elevated wooden panels (not exactly bridges)
• Cinder blocks
• Trenches filled with gravel

I'm re-laying some of the track and rebuilding the foundations, and would like some advice.

1. When laying directly onto a flat concrete base (e.g. cinder blocks), is there any benefit to adding ballast? For example, this post shows track layed directly onto the blocks, although there is ballast in the background of one of the pictures. If the concrete is supporting the track, does ballast do anything more than give it a realistic appearance?

2. As an alternative, lets say I have a concrete foundation but actually want to use gravel ballast to support the track. That is, the ballast will go under and around the track, not just fill in the gaps. I had previous dug a ditch, lined the sides, and filled it with about 10cm of gravel. The track seems fine, but I'm getting a lot of issues with plants over-growing and running weeds putting roots down through the gravel. I was thinking instead of using a concrete underlay with only 1-2cm of gravel to smooth out the surface.

Is this workable?

If I need to lay the concrete so that in places the track is elevated above ground level, are there any tricks to getting a "channel" in the concrete so the gravel stays where it should?

My rationale for laying concrete + ballast is that ballast makes the concrete base more forgiving, as it smooths out any irregularities in the concrete (rough surfaces or imperfect levelness), whereas its quite a bit of work to get either cinder blocks laid evenly (and there are gaps around curves for weeds to grow in) or to lay concrete with a perfectly smooth surface. And the concrete base blocks weeds from growing up.

Guidance welcome.

 

[Greg Elmassian]

How good do you want your trackwork?

This is an important question... short trains, light cars, sharp curves will tolerate much worse trackwork.

Why am I saying this? Because NO concrete block or slab is perfectly flat and level. This is where ballast lets you get it perfect.

Maybe you don't need it, but to give you advice one needs to know your expectations.

I run really long trains and where the track is on my custom poured patio concrete, I still need plastic shims to get it right. I have a long concrete wall that was made for a train track, and it is perfectly flat, but many hours were put into it getting it flat, finish grinding.

I would select #2 if it's not obvious by now. Track is literally the foundation of your layout, bad track and nothing runs right. Strive for perfection, and your effort will be rewarded in better running and more fun.

 

[Wistow vale rlwy]

Hello Andrew - I lay all my track on a concrete base of about 100 - 150 mm deep. I then use small plastic window packers to level/ cross-level the track. Then I mix alpine grit (or similar) with SBR bond ( a bonding agent used in the building trade etc - it's like PVA glue, but stronger and it dries white.) - I'm sure you will be able to find similar. I then pack this around, under and basically any where I can get it along the track, dressing the shoulder as I go. Once set, it holds the track firmly in place with no additional fixings - debris can be easily swept off without dislodging the ballast and it will also stand a light hosing-off. I've done this for over ten years, with a little repair to frost-damaged areas each spring. It works for me and I do like to see ballasted trackwork.

 

[Paul M]

No1, there is no need to put down ballast apart from making your line look good.
2, that would work, but you'd still need a fair depth of ballast, so you still may get weeds taking over.
As Greg says, a lot depends on what you intend to run. As I've a very small line I'm restricted to short trains, which is quite fortunate as my trackwork is anything but flat or level

 

[Andrew_au]

Why am I saying this? Because NO concrete block or slab is perfectly flat and level. This is where ballast lets you get it perfect.

I run really long trains and where the track is on my custom poured patio concrete, I still need plastic shims to get it right. I have a long concrete wall that was made for a train track, and it is perfectly flat, but many hours were put into it getting it flat, finish grinding.

I should have checked your web-site before asking!

I do like the idea of using a wooden runner embedded in the raised concrete wall. I notice from the pictures that the sides and kerbs are rough, but the central area is smooth. I assume that is the difference between the unground original and the carefully ground trackbed area?

From the site, it seems that you have a mix:

• ballasted track in the planters, with the ballast laid directly on the dirt and no extra binding
• free-floating track on concrete (but with some extra work to stabilise)
• track pinned to mounting beam embedded in concrete (with cosmetic ballast?)

I would select #2 if it's not obvious by now. Track is literally the foundation of your layout, bad track and nothing runs right. Strive for perfection, and your effort will be rewarded in better running and more fun.

What are your thoughts on bonding? You seem to have a mix of bonded and unbonded track. Occasional bonding points are obviously useful so that the entire layout doesn't drift over time, but it doesn't seem like gluing everything in place is necessary or even necessarily beneficial.

I've recently watched quite a few videos of smaller scale modellers, and it seems like they usually fasten their track to the baseboard / roadbed material and then the actual ballasting is mostly cosmetic (and possibly for noise reduction).

What I hear from your web site is that (for G scale) there are good reasons to have my track mounted (but not bonded) in a good coarse ballast. Have I understood rightly?

• When laying on dirt, is there value in a concrete underlay vs just gravel directly on dirt?
• When laying on elevated concrete, is there a good way of structuring things so the gravel doesn't just slide off / get washed away over time? I was thinking a shallow ditch about 12cm wide with raised edges, and laying gravel, track, and more gravel in that.

I notice some people lay varies roofing underlay or felt on top of concrete or brick. It strikes me that this would help smooth out irregularities etc, but I'm not sure I like the aesthetic and am concerned that it is another thing to catch debris.


Currently, the tighter parts of the railroad, including the parking yards, are on elevated wood (and mostly under a patio). The parts laid on concrete or dirt use gentler curves (mix of LGB R3 and R5) and only a few turnouts. Most trains are currently around 4 cars, though some cars are 50+cm each. Would like possibility of running up to (say) 10 cars in the future.

Thanks

 

[JimmyB]

I use a mix of block and trench, and as Greg Elmassian has pointed out even with blocks levelling is needed, and I use loose gravel for this. So I use ballast throughout my railway, it is loose, and does "disappear" from time to time, and will need topping up. The bonus is, as the ground moves, then the track can be easily adjusted, which may not be possible with fixed ballast.

 

[dunnyrail]

Currently, I have 3 different types of base on my railroad:

• Elevated wooden panels (not exactly bridges)
• Cinder blocks
• Trenches filled with gravel

I'm re-laying some of the track and rebuilding the foundations, and would like some advice.

1. When laying directly onto a flat concrete base (e.g. cinder blocks), is there any benefit to adding ballast? For example, this post shows track layed directly onto the blocks, although there is ballast in the background of one of the pictures. If the concrete is supporting the track, does ballast do anything more than give it a realistic appearance?

Have a look at my build linked in blue below.

Much will depend on what is under your track IE the topography of the soil. For my part I prefer a high level line laying Paving Slabs on 3-4 ft high walls. Of course the walls have a suitable foundation, but not that deep that a house could be built! Other areas are with wood either channeled U made up planks or full stations on Decking planks. These are supported on posts with fencing metal posts concreted in the ground. The wood has all been fitted with roofing felt and ballasted. Those pictures you show display another possibility again if you tamp the ground well they may work well for you.

As Jimmy says ballast in ground can help give you an ability to tidy up your track much as real railways have to do. If laying in a trench with ballast below it is worth while to put some kind of barrier in the trench before the ballast. I prefer strong black plastic with odd holes to allow drainage but many spurn that suggestion to use weed barrier, i find weed barrier to be less than effective as weeds can get a good hold in the barrier to be tricky to remove. Using plastic ensure ps that the weeds only get a grio in the ballast and are easily removed.

2. As an alternative, lets say I have a concrete foundation but actually want to use gravel ballast to support the track. That is, the ballast will go under and around the track, not just fill in the gaps. I had previous dug a ditch, lined the sides, and filled it with about 10cm of gravel. The track seems fine, but I'm getting a lot of issues with plants over-growing and running weeds putting roots down through the gravel. I was thinking instead of using a concrete underlay with only 1-2cm of gravel to smooth out the surface.

Is this workable?

Part answered above.

If I need to lay the concrete so that in places the track is elevated above ground level, are there any tricks to getting a "channel" in the concrete so the gravel stays where it should?

If you want a chanel in say a long concrete foundation to keep the ballast in I have in the past put a plank on a base where the track is to go, then top the cement up to be the same hight as the plank. Remove the plank and you have a channel. To assist removal of the plank I wrap it below and the sides with wast plastic from either the same type plastic I have used for barrier or from plastic bags that sand and ballast is supplied in.

My rationale for laying concrete + ballast is that ballast makes the concrete base more forgiving, as it smooths out any irregularities in the concrete (rough surfaces or imperfect levelness), whereas its quite a bit of work to get either cinder blocks laid evenly (and there are gaps around curves for weeds to grow in) or to lay concrete with a perfectly smooth surface. And the concrete base blocks weeds from growing up.

Guidance welcome.

Hope some of this gives you some ideas.

 

[PhilP]

Use a barrier to stop soil and ballast mixing..
If you use a coarser lower layer, your ballast will migrate into the voids over time.
If you create a 'channel', you will have built a canal! - You MUST allow for water to drain, here in the UK!
If you use wood as a base for the track, then cover with roofing felt. - It will last a lot longer. If you take the felt over the edge, let it hang below the level of the wood. This will let water drip, rather than 'wick' underneath.
You can add plastic 'D' moulding (as used by window fitters, does not have to be white) as a way to tidy up the edges. - It will also support your ballast.
Secure track at 'pinch points'.. Where it enters a tunnel, or bridge. Make the approaches straight. - Track is less likely to move sideways, as it exoands/contracts.
Be generous with clearances! Especially if you build with rock/concrete. - Nothing worse than not being able to run something you have *really* wanted..

PhilP

 

[Rhinochugger]

• When laying on dirt, is there value in a concrete underlay vs just gravel directly on dirt?

Let me declare my interest first (as per Greg's comment) in that I run narrow gauge, scale(ish) slow speed trains.

I am a dirt specialist and a long section of my track is laid on dirt, with a layer of geotxtile (weed proof - but not quite) membrane, then gravel that is no smaller than 6mm.

So the theory and actual is:

• The geotex prevents the majority of weeds growing up through from below - it doesn't stop things that have a bulb like bluebells and mombretia though, but a good weedkiller will nobble those.
• Also this system will not prevent some air-borne weeds from settling and growing - but it's not difficult to pull these out.
• The ballast size allows the use of a garden vacuum to clear off the leaves, and not suck up the stones.

My reasoning for no concrete is this. UK building regs now require a depth of more than 1 metre to guarantee no movement through frost heave or change of moisture level etc etc. Nobody is going to dig that deep for their model railway track, so whatever depth you go with your concrete, there remains a chance that it could move. So, if you've laid direct on the dirt and it moves, it's not going to be immensely onerous to lift the track, pull off the ballast, re-level the sub-base (dirt) and put it all down again.

I have some track on raised concrete blocks (brick-sized paviors) and I don't use ballast, there are also stretches running along timber sleepers without ballast, and a raised section on a ladder section which is open, so can't be ballasted.

It all looks reasonably OK to me, as, at some stage, the eye has to make the transition from the 1:20 railroad to the 1:1 landscape

 

[dunnyrail]

UK building regs now require a depth of more than 1 metre to guarantee no movement through frost heave or change of moisture level etc etc. Nobody is going to dig that deep for their model railway track, so whatever depth you go with your concrete, there remains a chance that it could move.

My foundations for 3-4 ft walls nothing like this and in 10 years here and similar at my previous house there was no movement with the walls laid on foundation around a foot deep or less, lots of rubble in the base with concrete above that to around 6 or so inches deep by about a foot wide. We all tend to do things different ways, what I did worked for me here, in Hemel before that in Luton and Hertford going back to 1983 oh and the Ruschbahn so I must be doing something right.

 

[JimmyB]

You can add plastic 'D' moulding (as used by window fitters, does not have to be white) as a way to tidy up the edges. - It will also support your ballast.

PhilP

I use uPVC "D" as you call it, but if you want to search for it, it,s correct title is "clocking"

https://www.amazon.co.uk/Cloaking-Fillet-Plastic-Window-Architrave/dp/B084G8R5QM/ref=asc_df_B084G8R5QM/?tag=googshopuk-21&linkCode=df0&hvadid=479961707199&hvpos=&hvnetw=g&hvrand=13350167751764147406&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045654&hvtargid=pla-1066732303856&psc=1

Photo of my bridges with cloaking to retain the ballast.:

 

[Rhinochugger]

My foundations for 3-4 ft walls nothing like this and in 10 years here and similar at my previous house there was no movement with the walls laid on foundation around a foot deep or less, lots of rubble in the base with concrete above that to around 6 or so inches deep by about a foot wide. We all tend to do things different ways, what I did worked for me here, in Hemel before that in Luton and Hertford going back to 1983 oh and the Ruschbahn so I must be doing something right.

Yep, I used my words carefully. What you can get away with, and what will guarantee an outcome are different things. I was making the point because I have seen quite a few instances where people said that they'd dug down 18 inches or so for a base for their railroad so that it would never move - unfortunately, that's a fallacy.

You are more likely to get soil movement in clay areas.

Equally, I wasn't talking about walls - if your'e going to build walls for a garden railway, then your decisions relating to foundations will be influenced by the soil type, and any previous use of the soil - trees, made up ground etc etc.

 

[PhilP]

Made up ground, even a walled planting bed, will settle horrendously (at our scale, by several feet!).

A good idea not to try to make your track bed too 'permanent', at least for a couple of seasons..
The only way round this, is to have supports (not wood!) into the subsoil before you add the fill.

PhilP

 

[Paul M]

Made up ground, even a walled planting bed, will settle horrendously (at our scale, by several feet!).

A good idea not to try to make your track bed too 'permanent', at least for a couple of seasons..
The only way round this, is to have supports (not wood!) into the subsoil before you add the fill.

PhilP

Definitely! Make sure your really happy with your design before you go mad and do enormous amounts of infrastructure work.

 

[Rhinochugger]

One other option with permanent structures for a model railway in the garden is to use reinforcement in both the concrete foundations and in the brickwork mortar courses.

Most of us understand the basics of concrete reinforcement, and for a concrete foundation under a small garden wall, it doesn't need to be too complex.

Reinforced brickwork is less common but very effective in strengthening both the vertical and the horizontal plane. Rolls of galvanised steel small diameter bar, ready spaced for either a half-brick or one-brick wall are available.

It all stems from the principle that both concrete and masonry are strong in compression, but weak in tension. Thus, if the ground heaves, while the low spot obviously sinks, the high spot causes the material to break its back. Reinforcement helps to bridge the gap between high spots.

While this may all sound a bit highfalutin, it does enable such structures to be smaller and lighter - which means less work

 

[ge_rik]

Aha..... Trackbeds and ballast. Garden railway modellers' favourite and probably most discussed and contested topic. I would say there are as many answers, techniques and variations as there are garden railway modellers.

As others have said or implied, a lot depends on the type of railway you intend to run. If you want to represent a rural, single track, neglected narrow gauge branch line then your choices will differ from someone who wants a high speed, double-track mainline. Fixed track and ballast have some advantages over floating track and ballast and vice versa. I opted for fixed trackbeds and fixed ballast - which seems to suit my slow speed, narrow gauge branch line and my infrequent running sessions.

It sounds as if you're heading towards a mix of floating and fixed. The important thing is that you are spending time seeking advice, weighing up your options and making an informed decision. Unfortunately, it seems that not everyone takes that route.

 Rik

 

[justme igor]

I opted for fixed trackbeds and fixed ballast

I think this is the best idea, with the thoughts of Greg Elmassian taking into the mix.
I just have a elevated bed trapped into two wooden fencing boards, plain dirt in it, covert with dpc folie.
2-3 cm of sand, 2-3 cm of (2-4mm) sharp gravel.
Every piece has in the middle a nail to keep it fixed, with enough room between the track sections to expand, but i run battery operated.
Seems to work fine at the moment, yes gregs site is a box full of gold...
With best regards Igor

 

[Paul M]

Try all the options you can, and see what suits you best. After all, as everyone says, each to his own and perhaps you might find 2 or 3 different ways works best for your line

 

[dunnyrail]

Well the debate about ballasting or not is a long term one for the forum as is whether to glue it or not. Perhaps a little help from the prototype may help with the glue question, seen at Paddington Station last monday morning.

 

[kedwards]

To ballast, or not to ballast, that is the question:
Whether 'tis nobler in the mind to go for the look.
The tracks and sleepers of G scale laid bare,
Or to spread the grit although it might cause troubles.

With apologies to William Shakespeare

LAID BARE


OR

SPREAD THE GRIT


I know which one I prefer.