# Overhead Clearance - What's the tallest thing on rails?



## acmartina (Jan 6, 2008)

Hi,

I have a couple of over-unders on my layout that have been "temporary" for several years now, and I am finally starting to get serious about putting in some proper bridges. I've got about 12" from railhead to railhead, so I think I have some room to work with, but I want to flexibility on the structure's depth.

Looking at my current roster, the tallest pieces of rolling stock are a Bachmann Annie and a LGB Mogul (balloon stack) that come in between 8" and 8.5". So 9" would seem comfortable, giving me 3" to play with. However, I would like to be able to accomodate visitors or future acquisitions. Going through the archives here and elsewhere, it seems USA double-stacks are quite tall. I saw 10" as a safe height in several posts. 

But what about some of the newer 1:20.3 locos like the Bachmann K27? Or some of the larger live steamers? How tall are they? Is the double-stack still the controlling height, or do some of these new leviathans exceed them?








Appreciate any advice. Thanks.

Steve H.
Cypress, TX


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## hcampbell (Jan 2, 2008)

Regner's live steam shay is about 9 1/2". I needed to raise a bridge. 

Harvey C.


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## stanman (Jan 4, 2008)

My tallest is the 2-truck Shay at about 9 inches.


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## toddalin (Jan 4, 2008)

Bachmann giraffe is pretty tall.


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## Dan Pierce (Jan 2, 2008)

Tallest is the 1/20.3 engines. 

I allow 10 inches for my clearance height and 5.5 inches for width. (Aristo snowplow needs this on straights.). 

Curves need more horizontal clearance for the long diesels and passenger cars, the USA trains are very long and overhang a lot.


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## H-man (Jan 4, 2008)

I heard from a friend that the Bachman K27 is about 6" wide at the cylinders so allow minimum of 6" clearance for these locos. Double stack needs a minimum of 9" from the base of the track ties to the bottom of the bridge. K27 needs minimun of 9.5" clearance from base of LGB ties to clear. 

I use the base of the ties as this is the easiest way for me. 

h-man


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## Steve Stockham (Jan 2, 2008)

Don't forget the caboose! My K-27 went through a tunnel just fine but my AMS bobber caboose scraped the top of it! I'd also be worried about the height of the Accucraft C&S #60 when it's sporting a Ridgway spark arrestor...


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## on30gn15 (May 23, 2009)

One way to approach the matter is that real RRs allow, I think, about 17 feet from railhead for minimum clearance. 

Pulled up calculator on this thing and in 1:20 that becomes 10.2 inches. 
In 1:29 it would be 7 inches 
Going with the 10 inches would seem to be the best bet?


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## barnmichael (Jan 2, 2008)

Posted By on30gn15 on 16 Sep 2009 12:01 PM 

Going with the 10 inches would seem to be the best bet? 
That sure messes up using 8" concrete blocks for your tunnel walls. Do they have 4"' concrete blocks?


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## Semper Vaporo (Jan 2, 2008)

You build with two courses of 8" blocks. But the bottom course is set an inch or two below grade and then after you have added roadbed and ballast you are closer to 12 inches to the top of the tunnel. Then you build a portal that is the height you want to "look" right. If you get a taller engine, you just replace the portals.


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## joechoochoo (Dec 27, 2007)

I made a tunnel portal from individuate boards w/ weather-proof finish. Determine the opening by mearsuring the engine height w/ a piece of track. My surprize was the caboose would not clear, had to notch it.


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## aceinspp (Jan 2, 2008)

Don't forget the stack pack cars. You will need considerable clearance to operate these cars. Later RJD


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## Nicholas Savatgy (Dec 17, 2008)

I agree with RJ stack cars i think are the tallest.... ASK ME HOW I KNOW.....


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## acmartina (Jan 6, 2008)

Thanks. How tall are they? I thought I read somewhere 9-1/2" was sufficient for double-stacks? If so, sounds like 10" will cover the waterfront. I will shoot for that.


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## SE18 (Feb 21, 2008)

My shortest locomotive is 8" tall (the ruler in photo is 7/8" scale). It is a tiny critter, operating on O gauge (32mm) track.


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## San Juan (Jan 3, 2008)

I think double stacks are the tallest cars running on the rails today. They are slightly over 20' tall. A close second would be Autoracks that are typically 19' tall. And not that any vendor will be producing "G" scale Amtrak Superliners anytime soon (I don't consider Great Trains Superliners to be scale models since they are way too short lengthwise), but Superliners are a little over 16' tall. Santa Fe Hi-Levels are slightly shorter then Superliners.

I bet a lot of modern era modelers will be looking into purchasing a few of the new USA Autoracks. Just be sure your line has adequate clearance for them. Otherwise this might happen:


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## Richard Weatherby (Jan 3, 2008)

Overhead clearance depends upon the tunnel portal. I have some with an arched opening which had a 10 inch center height. This was not adequate at either side, so I had to add an 1-1/2 inch under each leg, making the center 11-1/2 inches. When our club set up a modular display, the tallest thing on rails seem to be the LGB overhead repair car and anything that had the electrical panograph such as 2030 or Cockodile locomotives.



















My tunnels are 16 inches inside using 2 concrete blocks. Yes, you can get 4 inch blocks. The roof of the tunnels are 2 inch thick by 16 inch square or 24 inch square paving stones.
Clay flue liners are anthor alternative for tunnels but get the 13 inch size not 8 inch.


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## smcgill (Jan 2, 2008)

I'm using 11.5" from top of rails to bottom of any thing. If you go crazy with scratch building/kit bashing it might end up bigger than stock items.







when I run this I even get snow on top! It also accounts for settling/rises in track. I noticed this in the winter when the ground developed frost bumps. Good luck Sean


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## mickey (Jan 28, 2009)

What kid of pipe is this and how has it worked out? What kind of weight is it got above it?


Posted By smcgill on 23 Sep 2009 06:07 AM 
I'm using 11.5" from top of rails to bottom of any thing. If you go crazy with scratch building/kit bashing it might end up bigger than stock items.







when I run this I even get snow on top! It also accounts for settling/rises in track. I noticed this in the winter when the ground developed frost bumps. Good luck Sean


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## Pete Thornton (Jan 2, 2008)

_Here's how you find out! _











It's a model of the clearance car in the B&O Railroad Museum. Basically, it was pushed through whatever needed testing and the protruding bars would be moved to the clearance position. It was used after relaying track in a tunnel, for example.

The real thing has small brass protractors at the base of each arm, so you can read the deflection. With a pre-calculated table, that gives you the width through the obstruction. 
Alan has them laser cut in styrene - this one is in 1/29th scale, but he can make it 1/20.3 if you prefer! *http://www.thegalline.com/clearance18.html*


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