Tehachapi Upper Tunnels on a Shelf Module

[robert3985]

You can also run your ballast through a screen to get it finer. I use plastic micro filter screens from Small Parts Inc. to filter out N and Z scale ballast. I think I figured 3" to be the max ballast size for each scale.

Yup.  My measurements of U.P. ballast on the Ogden to Green River trackage indicates its average rock-size right at 3".  I screen a mix of Highball ballast and real rock I dug myself to get the right color mix, and use a screen with a .020" "hole" to allow irregular sized particles to make their way through it.  I then use a smaller screen to separate the smaller than .020" particles ( and a lot of dust) from the .020" ballast rocks. 

I keep a vacuum cleaner going close to my sifting/grading operation to capture air born dust particles.

I save the fine stuff for other scenic applications, like making game trails, or dirt roads.

[ednadolski]

Thanks guys for all the great tips about the ballast.   Say Lennart, any chance you might have a little bit of that #0311 minitec that you would be willing to sell? 

Meanwhile, I've completed the first RTV mold from the main tunnel portal master:



I just poured the RTV for the tunnel arch portion.   Once that cures, and I put together a few styrene dams, I'll be able to start making some plaster castings...

Cheers,
Ed

[svedblen]

...Say Lennart, any chance you might have a little bit of that #0311 minitec that you would be willing to sell? 

Sure, I can even send you some for free. Just PM me your snail mail address.

/Lennart

[ednadolski]

Thanks Lennart, PM sent, I greatly appreciate your offer!

The RTV for the tunnel archway is done, now I've got to get to town on those styrene dams.... then it'll be time to cast some plaster!





Ed

[robert3985]

Ed,

Cool, dude...

Can't wait to see the results!

[ednadolski]

First castings are done!  I'm pretty pleased with how these came out.      

Here are some pics, the plaster is still damp but I think the detail will show up better once I've painted & weathered these (got a few small air bubbles, but NBD to fill those in).

I still have a couple more of the styrene dams to make, every tunnel is different.   Then I also will be making the triangular wing walls to match -- so that will be another round of stripwood forms, concrete pours, and RTV molds.....







This shows the styrene dams in the mold, before pouring plaster:





Thanks for looking!

Ed

[GaryHinshaw]

Fantastic!!  I'll take one of each. 

Good to see the shot of how you set the dams up.  Is there a recess at the top of the main mold to produce the lip along the top?  Hard to make that out in the photos.

-gfh

[M.C. Fujiwara]

Looks dam fine!
Will have a great texture poking out of the hills!

[ednadolski]

Is there a recess at the top of the main mold to produce the lip along the top?  Hard to make that out in the photos.

Yes, it's easier to see the crown ledge in the mold in this un-resized image.

One thing that's not evident in the photos:  the dams actually form an undercut about 2 scale feet thick, along the top edge and around the sides.  This matches up with the way the proto tunnels were built.  If you look at the upper right corner of the tunnel in this pic you can see what I mean.  Normally it would be hard to cast something with that much undercut, but in this case it works because the styrene dams are removable and come out of the mold first.

I do usually get a fair amount of plaster seeping around the ends of the dams, until it starts to set up.   But other than being a bit messy it's not much of a concern, since it is easily removed after the plaster hardens.

Thanks! 

Ed

[robert3985]

Ed,

VERY interesting, and dam fine work if I say so myself!  Although the tunnels are much shorter than the ones I'm modeling on the UP in Weber Canyon, the portals you cast are nice and thick.  Do you line your tunnels? Do the tunnel liners from each side of the tunnels meet up in the middle?  Or do you do a "fade to black" on the tunnel liners so you can't see them very far into the tunnels?

Knowing your propensities, I'm going to guess that you cast up tunnel liners.  But, it will be interesting to read your comments.

[ednadolski]

Sorry Bob, I guess I'm going to disappoint you, I wasn't planning on doing any cast liners.  I did the fade-to-black on my previous layout and never would have noticed if there was anything else in there other than the plain black cardstock.  Plus in this case all the tunnels are different, with varying curvature, so it's a lot more effort than if I could make copies of a single straight length of liner.

I made a trip to the LHS to pick up some more styrene for making dams, so I should be able to resume that effort shortly.  Meanwhile, I've made some progress in the base module construction.   I started by printing out the plan full-sized, and then marking it up to show the subroadbed, track centers, tunnel portals, and other details.  I then laminated a couple of sheets of 2" foam board together, overlapping enough to create the 10' length of the module, and cut out the basic shape of the module with a hand saw.  I then made the end bulkheads out of 3/4" plywood, attached to the foam using Polyseamseal adhesive caulk (same stuff I used for installing ceramic wall tile in my old kitchen - that was a fun project too ).  I then used the hand saw to trim the plywood flush with the shape of the foam.   Next, I transferred the lines for the track & subroadbed onto the foam using a pounce wheel & Sharpie.  After that came the Woodland Scenics 2% foam risers along the track line (being careful to notch out for the plywood).

Here are some progress pics, with a few of the old plaster portal castings to show where the tunnels will go:





Next up is cutting the subroadbed out of 1/4" plywood and gluing it atop the risers.  Then it will be time to get some cork and track down! 

Cheers,
Ed

[M.C. Fujiwara]

You got nicer curves than some of the cougars in the ads on Railwire! 
Very much dig the flow.
This is going to be a great module: simple in design yet rich in detail and feel.
A tunnel portal into another world!

[GaryHinshaw]

Nice to see! This is going to be a real show piece.    (Actually, do you have any plans to show it?)

What are your plans for the scenery along the front?  Will there be a fascia at the edge of the foam, or will you extend the scenery down towards the creek bed?

-gfh

[robert3985]

Sorry Bob, I guess I'm going to disappoint you, I wasn't planning on doing any cast liners.  I did the fade-to-black on my previous layout and never would have noticed if there was anything else in there other than the plain black cardstock.  Plus in this case all the tunnels are different, with varying curvature, so it's a lot more effort than if I could make copies of a single straight length of liner.

Cheers,
Ed

Ed,

Very nice work as usual.  It's very interesting to see your well thought out work in-progress.

No, I'm not disappointed that you do the "fade-to-black" trick now that I see your tunnels are curved and longer than I had pictured in my head.  It has worked well for me also in past tunnel constructions.

However, I have made the decision to carve tunnel liners out of a single piece of super-dense 3" Styrofoam I was given for my twin, parallel curved, 18" long tunnels on my Taggarts module.  Don't know if it'll be worth the effort, but it WILL be interesting and something I have not attempted in the past.

(Edit:  I just read the entire thread, which answered two questions I asked, and which I have deleted)

[Flagler]

Hi Ed,the work looks great. I need to span a 5 ft opening to my work bench area and was thinking of using the 2" blue foam glued together.
Will this sag if it has no bottom support. I plan to make this a lift out section.

 thanks Flagler