Here is a variation which is all flat with all standard pieces of track and all O27 curves. It's easy to expand to an up-and-over. You have a zillion possibilities with O27 on a 5' x 9' table. My personal preference would be to engineer it with a variety of wider radius curves for easements and concentric curves. Do you plan to use any switches?

 Drawn with SCARM freeware

Hi OLDPA, your track plan kinda resembles D. Smiths layout that he posted on Youtube a while back;

This is close to your original idea. Grades are 2.9% and 3.6% for a 5-inch climb.

No switches as I run Lionel O27 and Marx on the same layout and I have not been able to reliably get them to work for both types of trains

I want some open space for accessories and I'm also thinking about room for a working drive in theater.

Greg

I run a variety of Lionel and Marx trains on a variety of Lionel and Marx switches, but not any Marx "fat wheel" locos which will only run on a Marx switch. Some of the older equipment has sloppy wheel gauge which stumbles on switches. I've found ways to fix that, but switchless layouts have the benefit of simplicity and reliability.

A flat layout is easier for running older conventional trains so you don't have to continually adjust the throttle for speed control going up and down the grades. A flat layout would also be easier construction and have more flat space for positioning accessories and buildings. You could use a 90-degree crossing for some track plan variety on a flat layout. A Marx crossing would handle fat-wheel locos. Another possibility is to have separate flat circuits on separate levels. One or two upper levels could be added later.

 Do you want to use all O27 curves? Marx used to make O34 curves which are handy for parallel tracks. Or the outer loop could be standard-O with O31 curves.

You have some very good points; I didn’t think about two flat levels. It would be nice to just let the trains with little input.

I don’t know anything about the Marx O34 track but it would make a nice turn, I guess I’ll look on ebay for some.

How would you mate up the O27 to O31?

oldpa posted: 

... How would you mate up the O27 to O31? 

Since you are considering separate independent circuits of track, I was suggesting that the outer oval could be entirely Standard-O with O31 curves. But it's not difficult to mix O27 and O31.

I just hammer the larger track pins into the rail ends of O27 track, then join it to the O31 track. It may help to first spread the base web of the O27 rail ends. Then use some transition shims under the O27 track because the O31 is about a quarter-inch higher.

The old Marx O34 curves paired with O27 curves make a nice double-track oval. There are also O42 and O54 curves in O27-profile (made by modern Lionel and K-Line), but they are not as readily available as O27 curves.

oldpa,

here's a track plan similar to your first without the elevations. A double 90° crossover. Ok, if you have no fat wheel geared models. My Lionel Jr. thumps over a modded 45°, but I wanted the track plan. half straights and cut to fit places, all 027. O42 outer loop, O27 inner loop. You can take the straight off of the small closed loop if you more drive-in space. The drive-ins are real estate eaters.

I have a friend in WA state with Marx 034 curves. Gives these layouts more options. Not so easy to find them. Many don't know about them. They confuse rail height with radius curve. Be careful if you try to buy any off of eBay.

That layout is very cool.  I think the track plan is used on the travel layout Atlas has.   I like the plan very much.

oldpa posted:

No switches as I run Lionel O27 and Marx on the same layout and I have not been able to reliably get them to work for both types of trains

I want some open space for accessories and I'm also thinking about room for a working drive in theater.

Greg    

A small drive-in theater makes a large footprint on a 5' x 9' layout. You might want to first plan out that feature so you can fit a track plan around it.

Custom Drive In Movie with Working Screen in O Scale

This O-gauge version in a you-tube video is at least 15" x 40", I reckon.

Would love to see this plan expanded to 045, 054, 063 curves.

My favorite track plan would be oval outside and oval inside with figure 8.  I would include two connections with the two ovals.

See picture of my control panel for two ovals and figure 8 , connection at bottom

The recommended track plan allows for trains to reverse in both directions and to change loops in both directions.

Do not be afraid of switches.  I use 27 Marx 1590 metal frog switches and have no problems running Lionel and all Marx even with fat wheels.

5 ft x 9 ft is a nice size.  If you want fun and action and lots features to keep attention for years consider building a turntable.  Mine cost $5 and was fun to build.  Check out my on going post on OGR forum, link below.

https://ogrforum.ogaugerr.com/t...ra-027-layout?page=1

 Post 9   6-25-2016    Turntable Construction

Charlie