Approximate Height at "Middle of the Road?"

[Ray Von]

Hi all,

 

I am laying the foundations for a straight section of road on my 'N' gauge layout, probably using fine grade wet n dry / emery paper for the final "surface" layer.  I want it to have a camber (ie:  sloping from the centre to the edges) and at the moment I am using layered graph paper.

 

At this scale the "bulge" is barely perceivable, and I am wondering wether to move on to thin card instead.  The question is: how high, approximately, is the highest point on a level section of road in relation to the lowest point (the gutter?)   

 

If I can get a rough idea of the prototype, I can start thinking about appropriate materials for scale.  Many thanks in advance! 

 

 

Edited March 15, 2019 by Ray Von

[gordon s]

This may help...

 

[Ray Von]

Cheers Gordon, 

 

So if I'm reading that correctly, the highest point is just 2% higher than that of the edge of the road?  (On a typical tarmac surface?) 

 

 

[TheQ]

I don't think I'd bother in N or come to that in 4mm, most roads round here in no way match that unless newly built.. putting in wheel ruts might be more appropriate...

[gordon s]

I would check the web for other info, as the first site I saw said 3cm height for every 30cm of width which would be 10%. That sounded far too high and I suspect was an error.

 

You shouldn’t be far out using 2-3%.

[kevinlms]

26 minutes ago, Ray Von said:

Cheers Gordon, 

 

So if I'm reading that correctly, the highest point is just 2% higher than that of the edge of the road?  (On a typical tarmac surface?) 

 

 

I doubt it would be much higher, it doesn't take much for water to run downhill,  which is its purpose. 

[34theletterbetweenB&D]

16 minutes ago, TheQ said:

... most roads round here in no way match that unless newly built.. putting in wheel ruts might be more appropriate...

That, and having the mean height vary along the length. It's only motorways and near motorway standard dual carriageways that are closely graded in most of the UK. Take a ground level sight along most roads that have been around many years and they 'roll' up and down. I suspect the greatest visual gain is first not having the road surface follow a baseboard plane surface.

[Ray Von]

I think I'd like to add the camber, I think if I don't I'll regret it - at least if I do it and it still looks flat, I can say "No, there's actually a 2% camber to that road!  .....You just have to have really good eyesight to see it!"  

 

As it stands there are a few layers of graph paper strips, which I painstaking cut into graduated widths, providing the "slope" and then another almost full-width strip over them to smooth the transition.

 

The "hump" can be felt, but I'm not sure if it's visually noticeable...

 

 

 

Edited March 15, 2019 by Ray Von
Typo

[34theletterbetweenB&D]

It will have an effect, even if the viewer cannot see how the effect is achieved.

[Ray Von]

Thanks, I'm thinking now about the possibility of creating the impression of height and depth optically as well as physically, ie: using a highlighting colour along the centre of the road and a darker shade at the edges, I think that together these two measures  might reinforce the effect.

 

Mind you, still got to buy the emery paper yet....

[The Johnster]

Looking at real roads, there is often a perceptible dip or alteration of camber, as well as a different appearance because of wear, in the 'wheel rut' area.  This area and the gutter edges are the prime locations for potholes, which you can either model as potholes (maybe with muddy puddles in them) or as patches.  Conversely, dust and debris collects in areas where vehicles never or very rarely actually go, in the vicinity of traffic islands for instance.  A suggestion of this is very effective, though you can probably spend too much time and effort trying to get it perfect and the suggestion is probably going to be enough in most cases!  

 

It is worth trying to suggest IMHO, though; the flat unicoloured roads with perfect right angle junctions seen on some exhibition layouts are one of my pet dislikes; these are the sorts of layouts where you know that's not going to be only glaring error and you are going to irritated by a myriad of over-bright lights flashing away, while 1950s traffic is held up by modern orange cones...

 

Another thing to pay attention to is road markings, and street furniture/traffic signs.  Roads are never black, or grey, or any uniform colour, and are mostly pretty faded and dirty places.

[Ray Von]

Thanks for all the input, chaps.  

 

The plan - at least in my mind - is to start with wet n dry / emery paper (as fine grade as possible) and spray it with grey primer.  This will be a base for consequent coats of paint, and not the final colour of the road surface!

 

I will cut the paper in such a way to mask the joins between sheets, and make cutouts for various patches and "repairs" and paint these in lighter and darker shades than the overall road surface. 

 

Hopefully, when the whole thing is laid and the patches are replaced and the whole thing is given a dirty coloured wash it should all come together...

 

 

[Philou]

A 'rounded' camber is likely to be a road built under the Macadam method where pitched stone was laid to a camber draining into a side ditch. The whole would have been dusted over with gravel. The water (in light rain) would drain through the stone and in heavy rain off to the sides - that was the theory. These roads were subject to potholing and erosion.

 

When 'tar' or asphalt became to be used, it was known as tarmacadam - the rounded camber plus a tar and chip topping which helped greatly in water-proofing the surface and reducing erosion. It then meant of course having to have drains to take the water away. The Johnster will know this as many of the older residential side streets in Cardiff take this form (and loads of pot-holes too).

 

On modern roads, certainly in the UK, the camber is more properly referred to as a crossfall. Currently it is 2.5% (1:40). Footways, IIRC, have a crossfall of 3.33% (1:30). The carriageway crossfall will vary with regard to the horizontal curvature of the road - similarly to the cant of a railway track.

 

If a highway is constructed in a flat area, false channelling is applied to both edges of the carriageway. Instead of surfacing the whole width of the carriageway in asphalt or other bituminous materials, a concrete channel is laid alongside the kerb that falls and rises over its whole length between gullies (drains). IIRC this is 1:100 and therefore the crossfall varies slightly as a consequence.

 

Gullies are laid always at low spots and one gully is laid per 225m² of carriageway surfacing - so don't forget to add a couple to your model road . As Johnster mentioned roads vary in colour and more often or not have patches on them where utilities have been laid/renewed/repaired (or pot-holes filled in).

 

Sorry about the length of the post but I worked years ago in highway design - some details I forget and others, no doubt, have changed.

 

Cheers,

 

Philip

 

[Dunsignalling]

6 hours ago, Ray Von said:

I think I'd like to add the camber, I think if I don't I'll regret it - at least if I do it and it still looks flat, I can say "No, there's actually a 2% camber to that road!  .....You just have to have really good eyesight to see it!"  

 

As it stands there are a few layers of graph paper strips, which I painstaking cut into graduated widths, providing the "slope" and then another almost full-width strip over them to smooth the transition.

 

The "hump" can be felt, but I'm not sure if it's visually noticeable...

 

 

 

 

It will become more noticeable with a few vehicles on it, especially where there is one close to another on the opposite carriageway.

 

John

[Ray Von]

Thanks again, 

 

Philip - I will definitely be picking your brain over the coming weeks re: this part of the layout, if that's ok?! 

 

It all hinges on the emery paper for now though, will be grabbing some tomorrow - all being well. 

[Philou]

No problem, Ray, no problem.

 

Cheers,

 

Philip

[Bomag]

Current minimum cross fall is 2.5% (See TD9/93); that can be from the centre or constant from one side to the other. 

[Philou]

Are 'they' (the DfT) still using TD9/93? E'gad, things don't change much.

 

Cheers,

 

Philip

[Philou]

If anyone is doing a 'modern' scene, there is the TSRGD 2016 (Traffic Signs Regulations and General Directions) that gives all the road signs and carriageway markings used in the UK and where and where not the signs may be used and combination of signs that are or are not permitted. One thing of note (especially to all drivers/cyclists) it is again repeated in the Regulations that if there is a system of street lights of three or more, and spaced not more than 183m apart (200yds), the speed limit is automatically 30mph if there are no signs to the contrary - rivetting stuff .

 

The document is useful as you can download them (Open Government) and use the symbols as a basis to create your own signs at a correct scale.

 

You will need to look elsewhere for the older style signs (pre-1966 I think). I have a link somewhere - I'll post it up later.

 

Cheers,

 

Philip

 

Edit: The Warboys Report was that which 'created' the signs as we know them today. Anderson was prior to that - but I couldn't find a direct link to the old signs - I'll look again and post if I find.

 

Re-edit: This link may be of use (includes Minic Motorway! amongst a lot of things on highways in general): https://www.sabre-roads.org.uk/society/links.php

 

Edited March 16, 2019 by Philou
Additional info

[Ray Von]

Wow, thanks Philip - that is really I useful info! 

[Bomag]

16 hours ago, Philou said:

Are 'they' (the DfT) still using TD9/93? E'gad, things don't change much.

 

Cheers,

 

Philip

 

3 hours ago, Philou said:

If anyone is doing a 'modern' scene, there is the TSRGD 2016 (Traffic Signs Regulations and General Directions) that gives all the road signs and carriageway markings used in the UK and where and where not the signs may be used and combination of signs that are or are not permitted. One thing of note (especially to all drivers/cyclists) it is again repeated in the Regulations that if there is a system of street lights of three or more, and spaced not more than 183m apart (200yds), the speed limit is automatically 30mph if there are no signs to the contrary - rivetting stuff .

 

The document is useful as you can download them (Open Government) and use the symbols as a basis to create your own signs at a correct scale.

 

You will need to look elsewhere for the older style signs (pre-1966 I think). I have a link somewhere - I'll post it up later.

 

Cheers,

 

Philip

 

Edit: The Warboys Report was that which 'created' the signs as we know them today. Anderson was prior to that - but I couldn't find a direct link to the old signs - I'll look again and post if I find.

 

Re-edit: This link may be of use (includes Minic Motorway! amongst a lot of things on highways in general): https://www.sabre-roads.org.uk/society/links.php

 

 

DfT don't build roads any more, anyway humans have not evolved since 1993 to drive safety on lower quality roads (in spite of what some 'professionals' may think)

 

TSRGDs from 2016, 2002, 1994 and 1981 are on-line along with most of the relevant Traffic Signs Manuals so you can print out the relevant signs for your layout. There are also some poor quality scans of the 1964 regs.

[DCB]

Ray does not say what era he is modelling.   Most of the advice is for current era.  However a couple of observations.

Almost no roads are level in the direction of travel.  Every road I have ever seen slopes if only slightly so water actually runs along the gutter.

I'm not sure when roads were coated with bitumen "Tarmac" but my Village Chedworth seems to have had the current network done somewhere in the 1930 era, 1928 has been mentioned and buses started in 1928 which ties in with this.

Not all were done, some still have not been done, and others were done later than the first tranche, the untreated roads being known locally as "Whiteways" due initially to the white dust in summer but the name has remained even after being tarmacked.  The situation changed during the "Big 4" era.

Single track Minor roads often have an exaggerated camber as the wheel tracks are pressed down while frost causes the centre to rise leading to grass often appearing down the centre,  The  old roads were often laid directly on the ground and over the years eroded deeper so they are below ground level with substantial verges. There is about 6" between surface and bed rock outside my house.

I have yet to see a convincing model road, one issue is the joins between sheets of emery etc are the very devil to disguise, not too bad in N gauge as a sheet covers a lot of ground.   The surface colour changes from shiny silver through  matt black to silver grey with rain showers, but laid on a level baseboard they will never look right, and the real killer.   Markings.  They should be near as dammit identical.  The guys paint them using a box template and take care to get them in line and evenly spaced.   I will have to have another go at my road after writing this.

Best of luck

[Ray Von]

Cheers David, 

 

The era is loosely based around mid 1970s to early 80's. 

 

I have been scrutinising roads a lot lately - because of the issues you mention above - and I have seen several surfaces that I could probably recreate fairly closely.  I have also seen quite a few "joins" too, that if scaled down would look just like badly positioned emery paper - so I'm more than happy that I can copy these "real world" examples!! 

[Philou]

Of course Ray, you could always do a concrete surface to your road. Plenty of those about too. They are/were laid in panels which may help in disguising your joints. Same rules would apply regarding crossfall and drainage. I reckon though you would have a devil's own job in creating a convincing concrete colour.

 

@David

Part of the problem of the exaggerated camber, especially in rural areas, is that successive 'maintenance' using 'tar and chip', would coat areas of over-run of the verges creating a thin crust on soil, that has little or no bearing quality. This is why kerbing is appearing on the inside edges of curves on rural roads as a verge protection measure - they're at it over here in France too - I know as I caught my tyre on an unprotected edge while avoiding white van man (they have them too) coming in the opposite direction at speed and over the centre-line. Wasn't best pleased as the tyre had only done 500km and was declared U/S.

 

Cheers,

 

Philip

 

Edit: The TSRGDs will give the precise thickness and length of road markings (some are dependent on the design speed of the road).

Edited March 16, 2019 by Philou
Additional info

[Ray Von]

Thanks for the advice, I think for now I'm going to stick to tarmac (!) 

 

I recall that when I was a kid the road outside my house was a sort of whitey-pink colour, because the surface was covered with red and white gravel, in later years it was tarmacked over - but in worn patches you can still see it.  I'd love to recreate that effect, but gawd knows how!! 

 

Anyway, just about to hit the "buy" button on a few sheets of P7000 grit wet n dry paper, this seems to be the finest grade available.

 

Thanks again!

 

 

Edited March 16, 2019 by Ray Von