# Tunnel Portal Dimensions



## bfrein (Aug 28, 2015)

I am planning on making my own tunnel portals. I am looking for the dimensions for the opening. This will be for smaller locomotives and cars....no double stacks or anything like that.

Gonna start on making my own trestle out of redwood later today

Thanks


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## John J (Dec 29, 2007)

If there is no curve close to the Portal I would leave a inch on either side of the track ties. I would measure my tallest car, smoke stack, and or Load. What ever is the tallest I would go about 1 inch to 1.5 inch above that. Or take the tallest object and make a portal that looks proportionate. There are not set rules. 

JJ


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## Phippsburg Eric (Jan 10, 2008)

I have covered bridges. I have rebuilt them twice! Each time I thought I had left plenty of space but I still got things stuck. I had a guest bring his 1:20 scale K27 which didn't fit the first bridges. So I built new ones. Then another friend brought his K36...dog gone it! But I didn't build new until I started building Maine two foot gauge in 7/8" to the foot scale. Some friends got some nice bridges! 

If you are modeling standard gauge stuff, and make the tunnel tightish you will possibly create a problem down the road when that Shiney 1:20 model catches your eye, or you really need a double stacker.


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## Totalwrecker (Feb 26, 2009)

"Smaller engines"
Which scale? That will help with the width of the openings. Since most engines and cars are under 14' tall I'd go with at least 8" from the top of the rail for the opening height. 
How wide you make the wings is up to you and/or your space.
John


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## The Tinker (Sep 11, 2014)

I am thinking between 10 1/2 and 10 inches high and at least 7 inches wide


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## Dan Pierce (Jan 2, 2008)

A good example of width needed is the Aristo snow plow, and height is the tall stacks on engines like the LGB bear trap and even the wizard on the LGB pustfix car. the tiop of the wand is very high compared with other rolling stock.
Note thet the Aristo plow willl not fit through the Aristo covered bridge!!. You would be mixing a 1/24 plow with a 1/29 bridge and LGB caboose marker lights are a tight fit with the end boards removed.


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## SD90WLMT (Feb 16, 2010)

As I have recalculated tunnel openings once again.. for F Scale

A K-36 is a good 6 1/2" wide over cab shades...
A 55 Ton Shay stack is all of 8" off the rails...

8 1/2" - 9" width is safe for a straight tunnel.. and perfectly centered rails
Running 10" - 10 1/2" , or more is safe for height. But again... measured from railhead...

Do have Phun with your toys!

SD


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## placitassteam (Jan 2, 2008)

My tunnels were 8 wide by 8 1/2 high. Some of my friends started bringing up to1/13 scale trains and even my K27 couldn't run with the spark arrester in place. I redid the tunnels to 10 1/2 inches high but left the width at 8. So far that is working. If there were any curves approaching or inside the tunnels they would have to be wider by an amount dictated by the radius of the curve and the overhang of the cars.


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