I guess I'm thinking these S curves aren't really S curves in the sense that I'm not having an 18"r curve followed by another one curving in the opposite way.   

I don't have all the layout completed, but the outer and inner loops are done, as is part of the mine spur (now becoming a granite quarry due to new managerial ideas).  I've run and backed 4 locos with varying number of cars through the questionable parts.  I've run them very fast and very slowly, with various speeds in between.

And I have not had a derailment yet. 

So I'm figuring the S curve problem in what I have already completed is not really a problem.  However, I plan to watch them as I completion the rest of the layout.

I do appreciate the input that has been deposited on this topic.  Thanks very much.

Thanks, Joe.  That helps.

Is the problem with S curves also speed-related?  If so, slight S curves in yards and industries would seem to be okay.

Just wondering.

I've heard it said that rules of thumb are fine--until fingers come into play.

Joe, you're right about the S curves.  One of the first things I heard when I posted on this forum in February was the problems caused by them.

In developing this layout, I kept that in mind, but it evolved to the point that the sweeping S beneath the Scenic Station was necessary.  I used flex track to lay it out, so it's actually straight for about a piece and a half of EZ track before it turns back. 

I've used EZ track for all the inner loop, as well as for most of the outer.  The curves are all 18" ones.  Flex track and Pecos turnouts comprise the new parts.  The industry turnouts and the yard don't use EZ track except for a left turnout to get in the mine and the yard.

I've run trains at varying speeds through the S curve in question and have had no problems.  So I think that will work. I haven't laid the turnouts, industry, etc. track yet.

As for the other western leg beneath the Office, I could sub a Peco left hand turnout instead of the Wye, if you think that would help.

That could be a solution for the other very slight S curves within the mine and the small yard.

I'm interested in what others think about these S curves.  I can make necessary changes before locking things down.

Thanks.

Thanks for the layout compliment Jerry, but much of it should go to Len for his recommendations.

I'm always open for improvements, such as yours about avoiding logging as requiring different locos, etc.

I will follow up on Len's excellent suggestion of switching from coal to another material.

One thing I'm wondering is just from an operational standpoint, how many tracks do I need in that industry area?

Or is that question one that can be answered only when the material mined or quarried is determined?

I am considering either a mining theme or a logging one, set in the Blue Ridge Mtns.  I suppose either would work, but I wonder which would be the most workable. 

The turnout to this industry is off my layout's mainline.  The turnout occurs at a flat section of a 3% incline and is 4" off the board.  It is a Bachmann 44130, which has an 18"r divergent leg (I know that's not the best idea, but that's what I have).  The "mine" would sit at a flat section at 4" above the table..

The picture shows a small yard at the end of the incline.

The left half of the layout extends the main line into a big loop.  There is also a turnout to a connecting line to the bigger world (construed as a Norfolk-Southern line).  In this other part of the layout is another turnout to an industry and another to an engine repair/storage shed.

The two loops are complete.  The sidings are in various states of completion and a station for scenic rides.

Right side of layout:
http://s1381.photobucket.com/user/kdgrant6/media/May%208%20-%20considering%20trestle%20to%20Mining%20Spur%203_zpsz48dxeat.jpg.html?sort=3&o=1

Left side:
http://s1381.photobucket.com/user/kdgrant6/media/1%20-%20May%2010%20-%20Left%20Side%20for%20Posting%202_zpschervjn5.jpg.html?sort=3&o=0

I would sincerely appreciate any suggestions.

Atlas puts track in theirs, at least in the ones I looked at.  Peco offers just the sides.

I agree, but I was not clear enough.  I meant: when do you encounter Truss-Girder bridges as opposed to plate ones?

Peco also has a Truss-Girder Bridge Sides kit, too.

http://www.modeltrainstuff.com/Peco-HO-Truss-Girder-Bridge-Sides-Kit-p/pec-lk11.htm?CartID=2

I don't know which one would be better.  Is there a rule-of-thumb is regard to which one you'd see in terms of prototype?

I ran into this Peco Plate Bridge kit:

http://www.modeltrainstuff.com/Peco-HO-LK10-Plate-Bridge-Kit-p/pec-lk10.htm

It's  just the sides of a bridge.  You take care of the road bed and attach the sides to make it look as if it's one piece.

I just saw this.  Incredible!  I know it's an old posting, but I felt the need to comment on such wonderful work.

Reminds me of a quote about Caesar :

Why, man, he doth bestride the narrow world
Like a Colossus, and we petty men
Walk under his huge legs and peep about
To find ourselves dishonourable graves.

Hi Jeff;
In the "real world" of this hobby, a lot of latitude can be used; but the one prototype practice they use is to use girders in the "upside down" fashion you mentioned.  I have seen this practice used where it looks like the track is "on top' of the girders. 
also, to KD Grant, there are several good books on bridges and trestles written by modelers. 
SGT C.
[/quote]
Have movie versions come out yet?
Seriously, though, any particular title you'd recommend?

Aren't there bridges/trestles/spans--something without track running through it--that would accommodate curved EZ track through it rather than having to flip it upside down?

Len, I'm afraid I can't quite follow this suggestion.  I don't understand the sideswipe thing.

Here's a pic of the piece I'm thinking of:
http://www.amazon.com/Nickel-Silver-Girder-Bridge-Atlas/dp/B0006KSKLK/ref=sr_1_1?ie=UTF8&qid=1431081412&sr=8-1&keywords=atlas+plate+girder+bridge

There's also a Code83 version that's a couple of dollars cheaper.  Although I'm running Code 100, it should work the same upside-down.
http://www.amazon.com/Nickel-Silver-Girder-Bridge-Atlas/dp/B0006KSKLK/ref=sr_1_1?ie=UTF8&qid=1431081412&sr=8-1&keywords=atlas+plate+girder+bridge

At least, that's what I'm thinking.

The piece itself, I think, is a 9" straight section of 100code track.  Will turning it upside down allow for a curved piece of EZ track to fit??

Could anyone recommend an HO scale bridge for a curved piece of EZ Track that crosses over a track beneath it?  The top track is on a set of Woodland Scenic 3% risers about 4" above the foam board.

Bachmann offers one in O and N scale, but not in HO.