Tunnel Portal Dimensions?????

[Anonymous]

Thanks,sorry no pics, here is a link to the "hotwire foam factory" RR gallery page..... lots of cool looking stuff there that can be made with their kits or homemade cutters:

http://hotwirefoamfactory.com/products/customer/gallery/2_modelrr.htm

the tunnel portals i made look just like the one in the photo tho a tad smaller.. think the portal in photo is for large scale

[Anonymous]

QUOTE: Originally posted by BigNumber99

Hi everyone, I make my own using a hotwire foam cutter & hot pen.. they turned out real nice

Welcome # 99. You dont happen to have a picture of them that you could post do you? This is the best idea I've read. I am looking for quick and easy. That is why I wanted ready made portals..........Tim

[ChiefEagles]

[:-^][;)]

[Buckeye Riveter]

I posted photos of my catch. I never saw yours, Chief.

[ChiefEagles]

The Buckeye engineer. [;)] He is a smart guy but can't fish worth a HOOT. [:)]

[Buckeye Riveter]

QUOTE: Originally posted by daan

.......Tunnels are never only round on top, it's actually an oval with one side flattened for the track. Simply because a curved wall can handle much more stress then a straight one. The tunnel portal drawn above will collapse in reality since the pressure of the earth pushing to the tunneltube forces the straight walls inward.........

Not quite right, my Dutch friend. The older European tunnels followed your rules of construction as did many olderAmerican tunnels. Today with the use of rock bolts, we can alter the force geometry such that the mass of the walls is increased dramatically. The straight walls decrease the expensive removal of the rock due to the smaller cross section. Another big factor in tunnels is the type of rock. Our eastern tunnels must be bored through sedimentary rocks and our western tunnels usually are going through metemorphic and igneous rock. Soft ground tunnelling is a completely different issue and plating and water are a big problem.

Someday when you visit the states, go see the Galitzen tunnels just west of the famous Horse Shoe Curve for a great lesson in tunnels. This particular bore had to be enlarged to handle the double stacks of Conrail and their small caboose museum tells you all about the process. (I hope it will still be there.)

[daan]

Welcome big number 99! You kick in with a great idea. Easy, clean and cheap.

[Anonymous]

Hi everyone, I make my own using a hotwire foam cutter & hot pen.. they turned out real nice

[Anonymous]

Make them big enough for Santa's reindeer horns to go through. I have to enlarge mine this year for Santa's Train.

Charlie

[Anonymous]

The MTH sinlge Portals are 4 1/4" wide in the opening and 5 5/8" tall in the opening.

[daan]

Tunnel entrences can easily be made yourself by using MDF and a hobbytool. To get the dimensions right (specially in a curve) tape a pencil in the middle of your longest car and let it run through your curve where the portal has to be made. the pencil will draw a line on the table (or paper) under the track on the inside. Then take your car which comes out the most in a curve and tape the pencil to the end of the car. You now have the outside needed spacing. The height is simple measuring.

In reality (rivet counting??) Tunnels are never only round on top, it's actually an oval with one side flattened for the track. Simply because a curved wall can handle much more stress then a straight one. The tunnel portal drawn above will collapse in reality since the pressure of the earth pushing to the tunneltube forces the straight walls inward.

Make a few try's out of cardboard and if it's satisfiying, draw that on a piece of MDF. Cut it with a jigsaw and sand the edges. Now you can draw stones with a pencil on it and with a multitool fitted with a small disc you can make the cuts between the stones.
Now take a piece of cloth and black paint and rub the paint in the cuts you made and on the stones. then do the same with white paint, but this time don't force the paint in the cuts. You will get a nice looking tunnel with all kind of shades of grey with blackish linings between the stones and it lookes good. (first try the cuts and the painting on some small retaining walls, to see if you like the result.)

in this way you can make every construction, from tunnels to bridges, retaining walls, houses etc.
Don't forget to shield the first part of the inside of your tunnel with some cardboard with painted stones or something, otherwise you can see right into the underlaying structure.

[Anonymous]

How about the inside width on the MTH tunnel portals? Anyone have this dimesnion? If no dimensions are provided on the MTH single portal by this evening, I will provide that. I too am interested in the K-Line and Lionel portal inside opening dimensions.

[Buckeye Riveter]

This is rough tracing of a Lionel portal. I think it is too low.

[wrmcclellan]

Tim,

The standard Lionel portals are 5" tall in the center. They are 5" wide at the bottom. The upper curved portion is a 2 and 1/2" radius. Thus the sides go 2.5" up and then the 2.5 " radius curve to the top center begins. I run scale and traditional, so I raised the portals by 1/2" from the base the track sits on. I use 0-31 tubular track, so the portal center is basically 5" from the tops of the rails.

I do not have any really tall stuff. A Lionel PW or Modern Era GG1 with the pantographs up will not go into the tunnel. So one needs to raise the portals another 1/2 to 1" for this to work.

Regards,
Roy

[ChiefEagles]

Tim, use to build my own. I now have some high cars [such as screeened car carriers and etc]. I am going to build mine to insure clearances for all the tall cars. If you do not, you can not run them through the tunnels and will eventually start replacing portals [and that is a lot of trouble]. Better to build them tall than too low. One way would be to buy their "ready made" ones and raise them on a big rock or concrete slab made by you. Good luck.

[Anonymous]

Thanks Lizard, I'll look to hear from you tomorrow..............Tim

[Anonymous]

I can give you the dimensions tomorrow of both MTH and Kline portals.

The other manufacturers include:
Lionel
K line
MTH
Mountains in minutes

all in O/027

I can say that the MTH portals are injection molded, and the K line are polyresin. The resin is much heavier, but the molded are hollow. So it's a personal preference type thing.

[Anonymous]

The web site for k-line and lionel give their portal dimensions but do not say if the dimensions are inside, outside or what. Iam looking for the inside clearance measurements on boththe single and doubles. Also if you know of another manufacturer of portals. I want clearance for the double stack containers in case I ever buy some. As always thanks in advance...............Tim Mitchell