Height for overpass?

Slawman

Slawman

Deckline
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I am beginning a new branchline today which will take my layout to another section of my yard (very exciting). The Pullit interchange will take the line to a lumber mill and chicken coop.....

This will involve elevating a section of track and bringing it over the top of an existing section.

My question is how high do I need to run this ie. what is the maximum height I am likely to hit with my trains.

Of course I have measured my existing stock and have come up with a clearance requirement of 18cm (from the base of the track).

Given this is intended as a long term endevour I am wondering what contingency I need to build in to ensure I do not find my clearance lacking for new locos or carriage sets?

I only have 4 meters to hit this so the lower the better to keep my grade to a minimum.

Many thanks all.
 
I guess it depends on a number of things. What type of railway will you run? Narrow gauge, standard gauge? Will it be based on Australian practice or some other country. What actual scale will you be running? What’s the predominant manufacturer you’ll be using, or will you scratch build?
 
I have 2 items of rolling stock that would fail that measurement, one is the Piko Kamel the other an LGB Beer Wagon with a Capula. LGB US Style Caboses will be pretty much the same problem and I have just measured my 2 items from the Rail Top. Both measure just on 18cm from the Top of the rail. You also need to add 2cm for LGB Rail Depth so 20 cm would be an absolute minimum I would have thought..
 
Martino said:
I guess it depends on a number of things. What type of railway will you run? Narrow gauge, standard gauge? Will it be based on Australian practice or some other country. What actual scale will you be running? What’s the predominant manufacturer you’ll be using, or will you scratch build?
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I run LGB narrow gauge at the moment with a bit of Marklin but who knows what in the future. If I do scratch build something that will be easy (I won't build it too high for my overpass/es) I am interested in the collective wisdom of the forum to help identify how far off 18cm is for other styles of loco. based on feedback from Dunnyrail, I might push it to 20cm....
 
If you're sticking with LGB or PIKO G scales (I or IIm) then 20cm might be enough with a few exceptions.
One is if you want to include overhead catenary, in which case you would need 25cm (from sleeper base).
The other is a bit more unlikely, which is if you want to run European narrow gauge rollwagens carrying standard gauge wagons, then you might need even more clearance.
 
Personnally I have 24 cm ( howe truss bridge and tunnel) .
Now I find that quite low. For example I cannot run the Piko Krokodil BR194 with pantographs extended.
This 24 cm was selected to allow a Bachmann caboose with its chimney to run through the bridge (Drawing courtesy from Garden Railways Magazine August 2016)
. 1533462841136.jpeg
 
This is an interesting and useful thread, as I've got to make some decisions my self very soon about setting the height of a couple of bridges over my ground-level loop - and like you, on one of them the lower I can get away with, the less steep the gradient will be on the bridge approach.
My collection of stock is similar to JonD's, in that it's mostly German NG prototypes, and like him my tallest items are likely to be a few box vans with raised brakeman's cabins and of course the Harzkamel; as long as these will fit I should be OK, because I avoid getting anything that has pantographs (not having overhead electrics run without any catenary is a personal preference, though I know a lot of folks are happy to do so) - any visiting electrics will just have to run with pantos down!

Jon.
 
Having just built my "over and under" I have 8 1/2 inch from the top of the track to the underside of the support.
 
idlemarvel said:
..........
The other is a bit more unlikely, which is if you want to run European narrow gauge rollwagens carrying standard gauge wagons, then you might need even more clearance.
Click to expand...

Hmmm, that's a good point Dave - will have to check if my rollwagen with the box van on it is actually taller than the Harzkamel! ;)

Jon.
 
If possible I would go for 24cms, that's what you need to the Rollwagen go through this LGB bridge:

DR-RollWagen-06.jpg

Thought I'd show a better picture of the rollwagens which does show how much larger the standard gauge wagons are compared with the narrow gauge stuff!

MixedTrains-06.jpg

The Standard gauge wagon certainly needs 24cms clearance ;)
 
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That looks like a narrow gauge (LGB) box wagon on the rollwagen Keith? A true scale 64mm gauge box wagon would be considerably bigger. On the prototype some of the larger standard gauge stock dwarfed the narrow gauge locos that were pulling them. Look at this picture of a Saxon IVK
images
 
idlemarvel said:
That looks like a narrow gauge (LGB) box wagon on the rollwagen Keith? A true scale 64mm gauge box wagon would be considerably bigger. On the prototype some of the larger standard gauge stock dwarfed the narrow gauge locos that were pulling them. Look at this picture of a Saxon IVK
images
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You are correct Dave, the last wagon is a narrow gauge wagon but the tank wagon is a standard gauge wagon (you can just see the buffers!).

Am hoping to collect a standard gauge box van (already ordered from my local Hobby Shop) at the end of the month which will then take the place of the narrow gauge box van.
 
A Stainz will need 190mm from rail bottom with little clearance so at least 200mm if you want a stainz to pass under.
You also need to think of what support superstructure is below your track when overpassing. In practice could be little more than a thin piece of galvanized sheet to support the top track. This will limit your bridge designs to ones with the superstructure above like in a Warren truss style bridge. Careful landscaping can hide the thin amount of support in tunnels etc.
 
ARIA31 said:
Can somebody explain me what is the need of Rollwagen in prototypical operation ?
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In the simplest terms, to move a standard gauge wagon on a narrow-gauge line. In areas with extensive narrow-gauge networks (eg: Harz and Sachsen regions in Germany) they were commonly used to move loaded freight wagons from the nearest standard-gauge mainline to a destination that was only served by the narrow-gauge system. Rollwagens are the full length low vehicles that the bigger wagon is rolled onto from a special ramp, but there are also "Rollbocks" which are like separate bogies that each support a single axle of the standard-gauge wagon.
It avoids the very lengthy and difficult job of having to unload a standard-gauge wagon and re-load the cargo into a number of narrow gauge wagons when transferring between the two gauge networks.

On the Harz (HSB), there are Rollwagens parked in sidings at the top Brocken station and at Drei Annen Hohne, each one carrying a standard-gauge tanker wagon as a firefighting water tanker.

Jon.
 
ARIA31 said:
Can somebody explain me what is the need of Rollwagen in prototypical operation ?
Click to expand...
Rollwagen
image.jpeg
Rollblock sadly only with a set of wheels, but a Wagon would sit on them the same way with a gap between the sets of small wheels which form a bogie for each end of a Standard Gauge Wagon.image.jpeg
 
Slawman said:
I run LGB narrow gauge at the moment with a bit of Marklin but who knows what in the future. If I do scratch build something that will be easy (I won't build it too high for my overpass/es) I am interested in the collective wisdom of the forum to help identify how far off 18cm is for other styles of loco. based on feedback from Dunnyrail, I might push it to 20cm....
Click to expand...

From my experience I'd go at least 200 mm min to 210mm if possible; I built a bridge to clear all my LGB stock (largest being 170mm high plus track height) only to buy a Bachmann 1:20.3 Shay (215mm including track height) and had to run it without the stack to get it under the bridge.

If it is crossing an existing line is it possible to lower that (a gentle dip) to get under it?
 
GAP said:
From my experience I'd go at least 200 mm min to 210mm if possible; I built a bridge to clear all my LGB stock (largest being 170mm high plus track height) only to buy a Bachmann 1:20.3 Shay (215mm including track height) and had to run it without the stack to get it under the bridge.

If it is crossing an existing line is it possible to lower that (a gentle dip) to get under it?
Click to expand...
That reminds me, the Garden Railway that I demolished last year had some LGB Track that had had just under a CM taken off the bottom of the sleepers. Not a lot but may help with the lower level. I had wondered why it had been done as there were no Bridges or Tunnels on the line, I guess it was to reduce the steepness of a climb a little. But would work equally well under a bridge.
 
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