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Roadway Under Bridge.


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Hi all, 

 

Have been trying to mock up a road to pass under a rail bridge on the layout, and I can't seem to get it to look right.

 

I think part of the problem is that I am limited with space, the length of the sloped section of road is dictated by the front to back cross members of the base board.  The result is a-not-overly-realistic incline, which isn't a huge problem - but it does give the impression of a jump, rather than a steady rise!

 

So far I have tried hardboard, plasticard, and cardboard as candidates - but they all look wrong and have been torn up!  I think I may have to use something that I can sculpt or form into a more gentle slope.

 

If anyone has ever tackled this issue or anything similar, any pointers would be greatly appreciated!

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Is there space under the layout to add a flitch under the timber in the middle of the baseboard that currently defines the necessary gradient to get the road beneath the rail bridge? If it can be stiffened in this way then the top of the timber can be cut away to permit an easier gradient.

 

This general problem of accommodating multiple levels is a reason for the 'open top' method of framing where there is no baseboard and the frame lies well below the model railway track level(s) enabling scenic features to be formed well below rail level. Track bed is made to the width of the formation and supported on vertical struts from the frame. See 'L-girder' for one of the best known techniques.

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I think that the problem visually is not the steepness itself but how you lead in/lead out to it. Real roads can be quite steep but they never have sharp "edges" to the slope.  I  would try to start the decent on the other side of the baseboard joint as it would not need much to be shaved down and curve the surface down over this. You want the surface to "pull out" with another gentle curve  before you get to the bottom surface.  If there is still not enough room have you considered raising the bottom road level and putting "low bridge" signs on the model? You could even model a cameo of the recovery of a truncated double decker.

 

best wishes,

 

Ian

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12 hours ago, Ian Kirk said:

I think that the problem visually is not the steepness itself but how you lead in/lead out to it. Real roads can be quite steep but they never have sharp "edges" to the slope.  I  would try to start the decent on the other side of the baseboard joint as it would not need much to be shaved down and curve the surface down over this. You want the surface to "pull out" with another gentle curve  before you get to the bottom surface.  If there is still not enough room have you considered raising the bottom road level and putting "low bridge" signs on the model? You could even model a cameo of the recovery of a truncated double decker.

 

best wishes,

 

Ian

 

Cheers, some good suggestions there.

 

I'm thinking of drawing the "side-on" view of the curve onto a bit of thin card and then using that as a template to cut polystyrene tile pieces. Once these are built "up" to the width of the road, I can insert this block and think about creating a surface...

 

Btw, found this pic of an early mock-up, I think it illustrates your point: 

 

 

IMG_20181127_082522.jpg

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Another problem you have is that plate girder, it needs to be moved so that it is centralised on the opening, not off set to one side. If you are putting non-concrete wing walls in, you will also need to introduce a batter into them (ie they need to be wider at the top than the bottom).

 

The roadway is very wide, is that what is making it look odd as well?

 

Andy G 

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8 minutes ago, uax6 said:

Another problem you have is that plate girder, it needs to be moved so that it is centralised on the opening, not off set to one side. If you are putting non-concrete wing walls in, you will also need to introduce a batter into them (ie they need to be wider at the top than the bottom).

 

The roadway is very wide, is that what is making it look odd as well?

 

Andy G 

 

 

Hi, yeah it does look a bit wonky right now - it's a bit hard to explain so I've just added some imaginary lines to an older pic.

 

The red line is the centre line of the bridge, the white is the road centre line and the yellow represents where the base board will be "filled in" to, and the top of a retaining wall will be added to match the one opposite (seen in earlier pics) - if that makes sense?  That should then make the whole thing more symmetrical....

Sketch203115641.png

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The topography would suggest a level crossing would be more prototypical/realistic. If it has to be a bridge it would help visually if the ground either side of the road also sloped down, and the railway was put on an embankment or viaduct.

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11 minutes ago, Titan said:

The topography would suggest a level crossing would be more prototypical/realistic. If it has to be a bridge it would help visually if the ground either side of the road also sloped down, and the railway was put on an embankment or viaduct.

 

A problem created by "flat-earth" baseboards rather than open top. A possible option, given the width of roadway, would be the Ely solution, a level crossing with a subway next to it for low vehicles.

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40 minutes ago, Titan said:

The topography would suggest a level crossing would be more prototypical/realistic. If it has to be a bridge it would help visually if the ground either side of the road also sloped down, and the railway was put on an embankment or viaduct.

 

I have a level crossing at the other end of the road! :sarcastic:

 

I hit on the bridge idea as a bit of visual interest, I don't mind if it's not entirely prototypical, and there are one or two bridges such as this near me that aren't too dissimilar to this one, although admittedly, they are more embanked.  So, this is my comprise to reality!

 

I'm quite happy with it so far, just waiting for the glue to dry, and then I can start evening up the surface and adding "tarmac!" :rolleyes:

 

 

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Couple of problems leap out at me, no dayight between bridge and backscene.   Continuing the wall under the bridge round to curve into the backscene will help.  No walls under the bridge yet, squeeze them in so you see bridge wall not much else will help.   I would raise the road level under the bridge to a few feet less than you show on the clearance plate and do everything possible to lengthen the grade down. Shave off the cross piece and lay the road surface on it, but up level to the top of the cross piece instead of layng 9mm ply on top. Having said that it need to level off before the bridge.   Road should be wet (gloss?) and dark under the bridge.

I would have lowered the baseboard and built the track on a sub frame on an embankment myself rather than having the road dive down.

Canal bridges are easier, many had minimal clearance and were very narrow, that's why many modellers use them, you can break a model canal boat in half and stick half under the bridge to completely block the view.  Keeping the water in can be an issue so maybe don't use real water.

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Cheers David,

 

The lack of daylight might be get-roundable, it's just that at the moment the layout is sitting up against a wall (I could put some daylight LEDs under there though...!)

 

The wall will indeed curve off to the right under the bridge the paint for that bit is drying as we speak.  

 

I don't think I will be hacking away at the crosspiece, it seems like a lot of work for a small pay off - the photo does make the dip look more extreme than it actually appears, I think I can tackle it with a bit of judicious "landscaping!" 

 

Thanks for the pointers, much appreciated! ☺

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I don't know if these photos help at all.

 

1432631162_wEly31322upgoods2ndApril77C3262.jpg.2811c8f218afb2e08f7267bf6361b2f1.jpg

Ely 31322 up goods 2nd April 77 C3262

The road where I am standing is almost at track level.

 

 

 

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Wolverhampton 86260 down pass crossing Lock Street bridge April 77 J5693.jpg

A lack of clearance here so it has bollards to close it off.

 

David

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The crossing/bridge at Bishton (South Wales) is interesting to look at.  No photos myself but the bridge is very low, not necessarily what you’re looking for but maybe something to think about for a future layout.

 

Cheers

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It reminds me of a real place, which is A Good Thing; Lowther Road bridge between Cathays and Roath under the Rhymney Railway in Cardiff.  This is a sort of 'flat earth' site where the road has been dug out beneath the railway, which runs at ground level here and which the road crosses at a 90 degree angle, and the approach ramps each side are contained by retaining walls which slope back a little; Google Earth should be able to show this.  It's a busy and popular short cut for both road traffic and pedestrians, and one of the pavements is built up to a higher level than the road, resulting in a very low headroom.  Steps let into the retaining walls allow access to side streets on the Cathays side.

 

Recent work on the drainage has eased the problem, but it has a notorious history for flooding after any decent rain, the reason for the high level pavement.  Local myth has it that the road is below sea level at the bottom!

 

The room you've got is the room you've got and you have to work with that, so any solution is going to be a compromise.  A mirror behind the bridge at road level may work effectively, as well as low bridge and steep hill signage on the road.  I'd be thinking of some sort of cameo on the ramp to divert attention from the backscene, perhaps a cyclist pushing his steed up the hill and putting his back into it.   Bollards because of low headroom may be another way to go.

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Lots of useful suggestions above, but to me the bridge girder looks too low in relation to the track bed - I'm not sure there would be such a deep track bed over the bridge, so raising the girder might give you a extra centimetre or so to make the slope less severe or increase headroom.

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On 20/02/2019 at 12:51, Titan said:

The topography would suggest a level crossing would be more prototypical/realistic. If it has to be a bridge it would help visually if the ground either side of the road also sloped down, and the railway was put on an embankment or viaduct.

 

There are real locations that originally had a level crossing as it was the cheaper option, but increasing traffic flows have necessitated removing it and digging an underpass instead to prevent congestion, especially at peak times.

 

Paul 

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