# tunnel portal height



## cape cod Todd (Jan 3, 2008)

Howdy All

I built a test tunnel portal for my RR using dimensions that I thought would be good and it doesn't look right. I used 12x12 flue liner for 3 of my tunnels so I built the portal 13x13 with an opening of 7" across by 10" high. What do you think? Most G equipment is 4" wide and my tallest engines are a LGB Forney with the beartrap exhaust and a Bachmann Climax. Last year I built a covered bridge that looks awesome using similar dimensions but it might be a little too tall . Before I go making 7 more of these does anyone have an official measurement for a standard tunnel portal?
Thanks 
Todd


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## Polaris1 (Jan 22, 2010)

My G gauge USA Double stacks measure 9.25" above the rail head.....
I made all my Over & under height clearance 9.625" tall over the rail head.... 


IF I ever need more height clearance, I can either pound the lower curved ladder down OR grind on the under side of the upper Bearboard plastic
wood road bed I bought from from Elgin, IL. See my Polaris1 profile for a layout picture.


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## stanman (Jan 4, 2008)

I used 10 inches too. My tallest loco is a Bachmann Shay at 9 inches.


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## Gary Armitstead (Jan 2, 2008)

This is a clearance gage I've had for my 1:20.3 narrow gauge stuff. Note the portal heigjht.


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## Greg Elmassian (Jan 3, 2008)

The tallest think I ever measured was the top of my balloon stack on my Bachmann 2 truck shay, 10.5 inches from rail top, as I remember. 

Regards, Greg


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## SoCalStu (Dec 27, 2007)

I'm curious as well. Anyone have modern double stack intermodal height? The tunnels they go through on the Tehachapi Loop look like they leave only inches of clearance!


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## kormsen (Oct 27, 2009)

4" width seems a bit smallish to me. 
if you ever plan to run LGB, you should add. 
my broadest LGB car, the post-car is 5"1/8 wide.


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## Greg Elmassian (Jan 3, 2008)

?? 

The drawing shows 4- 7/16" at middle, makes just under 9" wide... that scales to just a hair over 15 foot wide... 

Did I miss something? 

Regards, Greg


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## Gary Armitstead (Jan 2, 2008)

You're correct Greg. Center-line dimensions. Some just cannot read a print I guess.


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## kormsen (Oct 27, 2009)

well, i refered to this: 
I built the portal 13x13 with an opening of 7" across ... Most G equipment is 4" wide 
if one does not want to miss something, sometimes reading the question seems to be important too, to some at least... i think.


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## Dan Pierce (Jan 2, 2008)

My widest car is the Aristocraft snow plow. 

If a tunnel is on a curve, the opening needs to be wider as long cars/engines have overhang on the inside of the curve.


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## John J (Dec 29, 2007)

I built the inside of my tunnels to a hight of 12 inches. I made the portal 10.5 high. That way I can adjust the portal if I have to. 

I think I can adjust the portal


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## cape cod Todd (Jan 3, 2008)

Yesterday I put 3\4 inch corner moulding around the inside and outside edges of the portal I built and it looks great now. The opening was reduced by a fraction but it appears to be just right. I do have a few I need to construct for curved sections so they need a wider opening for the swing of my longest cars which is probably the USA crane and tender. 
I think I will affix 2 wires to the back of the portals such as ones used to hold up insulation and push them into the ground to hold the portals in place. That way I can easily adjust the height if needed. 
The portals are made from a piece of 1\2 inch plywood with lines scored in them every half inch up through just one of the plys. I plan on giving them a bath in a wood stain to help preserve them from the elements. I have built a couple of retaining walls in this fashion and one has been in place for 4 years and it is still holding up. 
Thanks for all the info guys. 
Todd


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## livesteam53 (Jan 4, 2008)

I make mine 7.5" wide x 11.5" tall for good clearance. Running 1:20.3 like a K37 you'll find you need it.


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