Bachmann Online Forum

Discussion Boards => HO => Topic started by: SteamGene on November 02, 2009, 04:01:43 PM

Title: Highway tunnel portal
Post by: SteamGene on November 02, 2009, 04:01:43 PM
Who has built a concrete highway tunnel portal.  I bought a double track Woodland Scenics, but it is much too tall, or so it seems, for even trucks.  How about cutting it down? 
Thoucghts?
Gene
Title: Re: Highway tunnel portal
Post by: lmackattack on November 02, 2009, 06:05:03 PM
I made one down at the club out of pink foam. I cut the porthole out and then lightly sanded the surface to give it a rough surface. Air brushed it and then put a year on it with a pen. I wrote on it hard so it looked like stamped concrete.

(http://i47.photobucket.com/albums/f200/lmackattack/th_MVI_1448.jpg) (http://s47.photobucket.com/albums/f200/lmackattack/?action=view&current=MVI_1448.flv)
Title: Re: Highway tunnel portal
Post by: SteamGene on November 02, 2009, 08:42:23 PM
No.  HIGHWAY TUNNEL. 
OTOH, what you did looks very nice,
Gene
Title: Re: Highway tunnel portal
Post by: lmackattack on November 02, 2009, 09:08:56 PM
Hi Gene.. I did see that your making a street tunnel. I think you could use the same Idea as I did as mine turned out pretty good. you can do the same just smaller for trucks. That porthole is made to clear doublestacks and auto racks. Semi trucks of today are 13.6' a 14' clearance is plenty for todays standards
For early 1940s-1960s 12' -12,5' trailers were common so 12,6' would have been a common hight in a small town. Here in Chicago you can still find 10' -  12'  - 13,6'  "EXACT" bridges only large interstates would have built tunnels to over exceed a normal truck hight as most trucks with oversized loads cant use tunnels...

here is another concrete tunnel at the club Its nothing more than wood with some weathering
(http://i47.photobucket.com/albums/f200/lmackattack/IMG_1759.jpg)
(http://i47.photobucket.com/albums/f200/lmackattack/IMG_1758.jpg)

fast forward to :50 to see a vid of that porthole I made
http://www.youtube.com/watch?v=C7m-Pjx23hI&feature=related
Title: Re: Highway tunnel portal
Post by: Jim Banner on November 03, 2009, 12:45:16 AM
Unlike railroad tunnels which are often ventilated by trains pushing air through them, road tunnels either have to be higher than the bare minimum required for clearance or they have to be force ventilated.  The Mont Blanc Tunnel is only a little over 14 feet high and uses huge fans blowing in at one end and sucking out at the other.  The Holland Tunnel is similar and uses fans totaling 6000 horse power, costing hundreds of dollars every hour to run. 

For shorter tunnels with lower traffic densities, higher roofs can provide enough ventilation just by chimney effect, particularly if vertical ventilation shafts are used and/or the tunnel is sloped instead of level.  This may account for the seemingly high portals.

Jim
Title: Re: Highway tunnel portal
Post by: jward on November 03, 2009, 07:05:31 AM
noch makes a line of tunnel portals in ho and maybe n scales which are foam. you can cut them down easily to reduce their height, something that is hard to do with woodland scenics portals, which are plaster. you might try using a double track n scale portal, that would probably look right.
Title: Re: Highway tunnel portal
Post by: SteamGene on November 03, 2009, 11:40:12 AM
Thaks.  I hadn't thought of N scale.  OTOH, it struck me that I could use the Wodland Scenic tunnel and then claim the Pensy Turnpike excuse - the tunnel's builder's was a railroad that never got built! <g>
Gene