Tunnel Portal

[Anonymous]

Would a tunnel portal be recessed into a rock-face or sticking out?

[selector]

Probably near-flush, maybe a couple of scale feet out in front of it only. A lot depends on the type of rock, how strong it is, how much it scabs and falls down over the tracks and to the sides. Will there be retention walls to the sides?

I don't think I have ever seen recessed portals. The company would just have left a rocky entrance if that were the case...no portal structure needed due to the extra-stable and strong rock.

[Anonymous]

Thanks...Not too many tunnels in my neck of the woods. I think I'll just work in retaining walls on either side.

[selector]

Okay, although I did build in two 'stone' portals and a lumber one by Woodland Scenics. They are semi-recessed, and look quite good. Only my lumber one has retaining walls.

By the way, steam or not, don't forget to smoke up the upper edges and top facing of the portals/tunnels with diluted black acrylic paint for that realistic look.

[Anonymous]

I'm a fan of the NS Rat Hole which still has several tunnels. I noticed the portals stick out quit a bit on some tunnels. It makes sense to me. If you are tunneling through soil instead of rock you need to account for errosion.

[Anonymous]

QUOTE: Originally posted by selector


By the way, steam or not, don't forget to smoke up the upper edges and top facing of the portals/tunnels with diluted black acrylic paint for that realistic look.

I've heard of holding the painted portal over a burning candle to have actual soot at the top of the portal-top to simulate engine smoke. Anyone ever try this?

[selector]

I hadn't thought of that! Don't see why it wouldn't work. The only drawback, or caveat, better, is that the smoke/soot will be fragile and easily dislodged (by fingers, usually). The paint dries hard to the surface, and if dullcoated, will stick. Then again, it takes some perisitence to get it to look decent. I don't know how soot will respond to Dullcoat.

[bogp40]

Most portals are positioned out from the bore itself. Even solid, very stable granite will errode and crumble. If the portal was flush or recessed, w/o the protection of a shelf rock slides would end up on the tracks. Areas of sedimentary rock, some portals can be extended 100 ft w/ concrete stucture/ tube extending into the hill. But for modeling purposes, you need to use modelers license in most cases to fit the scene. If it means that the "Woodland Scenics" portal is flat against the rock molds to look good, then so be it. You can't always model the real world to a "T".
Bob K.