Space Requirements 2-rail O

Well, you might think more about operations.   Generally yards are not the focus of the operations, the industries along the line are.   And industries along the line add a lot of neat scenery in many cases.    Yards are just devices that are used to support the operations to the industries and a nice operating scheme could be done without yards at all.  

I have found that 48 inch radius works fine for many steamers in O 2 rail.   For PRR models, many of the prototype and many of the models up through 4-8-2 had blind drivers so they go around curves quite easily.   I am not familiar with Santa Fe stuff.

Generally though 2-8-0s and smaller would probably handle 48 inch radius very easily and depending on loco, probably tighter.     Mikados would probably be a 50-50 guess but I am thinking most would work.   My PRR mikes do not have blind drivers and do fine on 48 inch radius     If you go bigger to mountains or 2-10-4, then you will have to check each one out.    I have a few Sunset GGD brass steamers and they not problems with 48 inch radiuis and most would probably go tighter except the 2-10-2.

40 and 50 ft freight cars will be fine on 48 inch radius and probably work down to about 36 inch, especially 49 ft cars.    And these work with body mount couplers.     Newer GGD 80 ft passenger cars, or older Walthers cars will go around 48 inch radius without complaining.    Many brass 80 ft cars will not without modification.   These usually have a lot more underneath detail and that stops the trucks from swinging far enough.    

I think any 4 axle diesel will handle 48 inch radius.     I prefer single motor drives and mine handle 48 inch radius with no problem.    These include weaver and all nation units.   The locos will go around 36 inch radius but the coupler swing becomes a problem at some point.   I think it would work on 36 but not less.    I also have GGD E7s, SD7, and PAs and I tested them on 48 inch radisu and they ran fine.    My main line has  52 inch minimum and my branch has 48 inch.    Newer Atlas and MTH 2 rail stuff has the truck mounted motors and will go around sharper curves more easily in most cases but in my experience to not run as smoothly, all else the same.

Brass 4 axle diesels would probably work on 48 inch raidus, but some high ends probably not.   

In the old days, 40 inch radius was considered adequate for 2 rail O gauge.     If you look at early John Armstrong track plans in magazines, that is what he  uses.    However, as models have become more detailed the radius needed for steamers in particular has increased.    You could easily run 4 axle diesels and 40 anf 50 ft freight cars  using 36-40 in radius and still have body mount couplers.

This is not advice, just giving you some of what I have learned from experience with O 2-rail    I think you are right that O 2-rail is more available than S.   Especially if you got the O scale train shows.    A lot of new-old stock and  used stuff shows up and there is a huge amount of variety of locos and rolling stock.

I too have 48" radius minimum on my layout and run 4 axle diesels (1960 era) along with GGD E8s  and RDCs for passenger/commuter service.  I have and run 80 foot passenger cars from GGD with no problems.  I think if I were to build the layout over again I would try for 52" radius but I am not really having any problems running trains even on a 2-1/2 turn 48"/54" double track helix with a 2.1% grade.  For freight I stick with shorter steam era cars in the 40-50 foot range.  when mixed with 34' tank and hopper cars the trains look longer.  By the way Key and sunset PAs need 54" radius as a minimum even with chassis modifications as the long trucks are the problem (don't ask me how I know).

A lot of 'classic O scale' guys will chime in telling you that 60" or 72" is the barest minimum.  That is great for looks and running 4-12-2s or Big Boys. I agree that 80 foot passenger cars look MUCH better on 60" radius but if you want more than an oval you can certainly get by with 48" or 52".  I have a buddy that has 36" radius and runs 4 axle diesels.  The layout has beautiful scenery, structures and bridges and overall looks great.  He disguises the 36" radius turnback curves at the ends of the layout behind trees and buildings.  Most other curves are far wider on the straighter sections of the layout and look very natural.   His space is (I'm guessing here) 18x26 feet and the benchwork is "E" shaped with the vertical bar of the "E" against the 18 foot wall.  The center leg of the "E" is a peninsula down the middle of the room and is shorter than the other two legs along the long walls so they can blob out for the turnback loops.

@prrjim posted:

Well, you might think more about operations.   Generally yards are not the focus of the operations, the industries along the line are.   And industries along the line add a lot of neat scenery in many cases.    Yards are just devices that are used to support the operations to the industries and a nice operating scheme could be done without yards at all. 

I have found that 48 inch radius works fine for many steamers in O 2 rail.   For PRR models, many of the prototype and many of the models up through 4-8-2 had blind drivers so they go around curves quite easily.   I am not familiar with Santa Fe stuff.

Thanks Jim. Lot of good stuff to consider.  I appreciate your insight.  Lot here to consider.

As far as operations - I'm very much into the models themselves and the nature and rural scenery - not super interested in industry and operating - unless it's a backdrop or something for a train to run behind.  I like Gary Schrader's layout which is mainly a giant scenic double main with some bridges and an engine house. He's got two large storage yards which I would never need - and I could never afford half the locomotives he has - but it's a good starting point.   

I could see having an icing platform to accompany my engine house - mainly for a place to stockpile and display a variety of ATSF / ART ice reefers.  Maybe a siding or two for boxcars to pass by - but nothing to extensive - especially given that space is limited - and rural scenery is ideal.

That's why I've also been looking at S - get me a little more freedom to expand rural scenery.  But the availability is very limited - and the cost - from what I'm seeing is skyrocketing.  The SHS stuff is regularly selling for $60-80 a boxcar when I can get nice highly detailed Atlas O for under $40 - and I have local used shops - with S - I'm limited to online and shows.  My thinking is the more I save on rolling stock, the more I can dedicate to obtaining some nice locomotives and scenery.

It sounds like you are more interested in creating detailed scenic elements, kind of like dioramas, within an operating railroad, without modeling railroad operations.  If that's the case, I say go for it and have fun.

You may want to somehow create view-blocks between your scenic elements for decent photo purposes.  And, for car storage and switch-out purposes, nothing beats a small interchange yard (only one or two tracks) where competing / cooperating railroads intersect.  That intersection will have a tower (maybe old and abandoned), lots of signals and other nice details.

Chuck

Another  options, whether S or O, is to go around the space, with the viewing/operating space in the middle.    This does two things.    First the equipment on sharper curves looks much better when veiwed from inside the curve.    Second, for any given space, an around the walls design gives more square footage and hence more scenery etc.

Keep in mind that a given radius/diameter takes up the same amount of space, regardless of whether you run O, S or N scale.

Odd guy out here - go for the largest radius possible on an outer loop.

I literally expanded my train room two feet to get to 74" radius.  It was worth it to see the big Baldwin 60000 run double-shotted with SP-class 3 cylinder locomotives in 17/64.  And I don't need giant spaces between my diaphragms.

Inner track can be anything you like - you don't have to run PAs and Pullmans on industrial sidings.

@PRR1950 posted:

It sounds like you are more interested in creating detailed scenic elements, kind of like dioramas, within an operating railroad, without modeling railroad operations.  If that's the case, I say go for it and have fun.

You may want to somehow create view-blocks between your scenic elements for decent photo purposes.  And, for car storage and switch-out purposes, nothing beats a small interchange yard (only one or two tracks) where competing / cooperating railroads intersect.  That intersection will have a tower (maybe old and abandoned), lots of signals and other nice details.

Chuck

Yup. You got it.  I grew up visiting train yards. Lawrence, Topeka, Emporia.  Dad worked them all when I was a kid.  They are fine - but I find they tend to take over - and are all kinda flat and same-y.  I tend to just like a train running through purely scenic elements - which is what trains are doing the majority of the time. Crossing Open Country.   I like how Gary Schrader uses bridges to link up islands of benchwork in his layout space.  It allows him to get good scenic views from both sides of his double mains.  I'd probably stick with a single main for my own. 

@Richie C. posted:

Keep in mind that a given radius/diameter takes up the same amount of space, regardless of whether you run O, S or N scale.

Very true - but radius requirements are very different for a Northern in S and a Northern in 2-rail O so it's nice to get some perspective on what's possible.  I tend to like bigger trains in a less accommodating space - I feel that cranks up the rail fan perspective.

After 45 years of running HO, O 2 & 3 rail. I am moving to S scale, a little late...yes. But I was thinking the same as you for lack there of supply. I went overboard in buying in HO and O, I can't do that in S. I had so many HO engines when I went back to it from O that I kind of lost interest in trains.( I did the same thing in 3 rail) With MTH leaving the market, your choices for engines just got more expensive. Outside of finding Weaver, MTH and Atlas on the second hand market now, Atlas is also spotty on new engines for 2 rail. Now all you have left is very expensive brass, but where as freight cars are all over the place.

I have found so far everything I need for S scale, I am using code 138 rail flex track with lionel fastrack R27 manual switches so I can run both wheelsets. The product is out there for S, you just need to find it. That is what a lot of S guys have told me, it's not as bad as you think it is. I was worried I was not going to be able to get enough steam engines I wanted, I was wrong. I didn't get the wheel arrangement I truly wanted, but I will be able to fill my steam engine roster within the next few years. Same thing with diesels, they are out there.

S is a great size, but GOOD LUCK finding stuff. You have plenty enough room for a decent O layout. Make your radii as big as you can.

I tried S briefly, and your choices are waaaaaaaay limited.

Simon

@Simon Winter posted:

S is a great size, but GOOD LUCK finding stuff. You have plenty enough room for a decent O layout. Make your radii as big as you can.

I tried S briefly, and your choices are waaaaaaaay limited.

Simon

This is certainly true. S is probably the best size for what I want to do - but O might be easier to accomplish with.

I'm happy with some decent Pullmans and a wealth of Single / Double Sheathed Boxcars and Ice Reefers - which would have been the primary freight seen on mainline in eastern Kansas.  The freight are available in both O (Atlas) and S (SHS) but it seems demand for S is higher than I've anticipated and cars are selling for twice what I expected.  $60 a boxcar ain't happening - and everything I've found has been near or at that.  Atlas adds the single sheathed 50' which aren't available in S and there are alot more road names across the board in O (Frisco, MKT, Wabash, Rock, MoPac are all pass through favorites of mine).  $30-40 is acceptable cost in my mind.

AM has nice looking pullman coaches  for cheap.  GGD did some I believe in O 2-rail though I've never found any.  I expect those to be about $50-75 difference in price per car - which isn't bad.  Could go up to lightweights as well - AM Budds vs GGD or Kline in O.  GGD is trying to make them in S but I doubt that happens and they'll be beyond my means - for sure. T

Looking at power:  There's only a few steam options for ATSF in S  - AM Northerns, SHS 2-8-0s, and generic AM 4-6-2s.  There are a few leased options but nothing to write home about. Expensive Brass Berk, a Lionel y3 (yuck), and Lionel is working on their own ATSF Pacific.  Cost on most used is in the $300 range which is good.

Comparitively, there are more options in O 2-rail for ATSF from MTH, Pecos, etc.- but $300 is probably base for most.   I had a line on 3 Pecos 4-6-4s a few years ago - should have bought them.  Sunset long-term I might be able to add some power - not at new cost though.  I do follow the online auctions for 2-rail but I feel like the engine prices have doubled in recent years.

I think Jacobpaul81's conclusions above are basically correct. In S there is less available and most things cost more, plus to fill a given square footage of space it takes more 1/64 buildings than it would 1/48th buildings. All the bridges had to be custom built. The passenger station platforms had to be custom built. Virtually anything one needs is available off the shelf in O, a much cheaper approach.

Track is not an issue in S if code 100 is used. I had to use code 138 so high rail equipment could be run. That meant all 45 of my numbered turnouts had to be hand built. 1/64th scale structures are limited. I had 20 custom built from scratch for the city area.

I was very fortunate that I had the budget to do this in S scale. The incremental cost to have all these things custom built in S versus the cost to buy them premade in O scale was at least triple according to the layout builder.

My minimum radius is 30", equivalent to 42" in O scale. I can run freight cars with body mounts as well as the short AM passenger cars, equivalent to an 18" car in O scale. I also run full scale passenger cars, equivalent to 21" cars in O, but only with truck mounted couplers. The bare minimum to run the scale passenger cars with body mounts would be 36", equal to 48" in O. That will allow running many, but not all, of the River Raisin scale steamers.

Interesting comment on the S gauge Y-3 from Lionel. I think it is a great looking engine with a lot of applied details. Based on the (yuck) rating of Lionel's finest in S, that leaves River Raisin. RR steam engines are, with DCC and sound, just about $3,000ea.

@AmFlyer posted:

Interesting comment on the S gauge Y-3 from Lionel. I think it is a great looking engine with a lot of applied details. Based on the (yuck) rating of Lionel's finest in S, that leaves River Raisin. RR steam engines are, with DCC and sound, just about $3,000ea.

Please understand - the Y3 comment is more about choice of model and not the model itself.  From a historical perspective - it's a unicorn.  In order to keep up with demand during the war, ATSF shifted all their helpers to long haul freight duties and they acquired some Berkshires (also a unicorn) to help out for long haul work. But they needed something to help get stuff over Raton, so they purchased some Y3s around 1943 cause that's all that was available. They promptly sold them around 1946-47.  The Berkshires were also sold off at the same time.  They were both acquired in very small numbers and not particularly good locomotives.  ATSF was a mostly Baldwin built road which relied on a fleet of Prairies, Mountains, Mikados, and Northerns for most of their mainline freight service. 

Ok. There is a lot of historical inaccuracy in the Lionel AF road names offered on their engines. I tend to ignore it, mostly because I have not researched or studied what railroads owned what engines.

@AmFlyer posted:

Ok. There is a lot of historical inaccuracy in the Lionel AF road names offered on their engines. I tend to ignore it, mostly because I have not researched or studied what railroads owned what engines.

It's a problem across the board - not just with Lionel, but all manufacturers - even the brass importers do it.  At least in the Y3s case, the ATSF owned a few - if ever so briefly. 

For about 3-4 months I seriously contemplated switching to S but decided against it. The reason was I like steam and I couldn’t find very many examples of steam engines for the railroad I wanted to model. I found tons of diesels though. If I were a diesel guy I would have made the switch. Later on I did find some brass models but they were very, very expensive. Another thing was I had spent over 15 years building my roster which I found hard to give up. Also selling my O scale collection (which for practically all of the locomotives would be at a significant loss) and buying those very expensive brass models would have been a very large downsizing of locomotives. I wish you good luck in whatever you decide.

Whether you choose S or O scale, you should consider having a staging yard where you can store trains.  This is especially true for a display type layout where trains are going to run through scenery once and then exit the "stage".  You will need a place to spot your trains for their next run.  There is nothing more frustrating than having to remove a train from a layout every time you want to run a different train.  

Staging yards can be hidden or open.  Many people build a staging yard in an adjacent room.  Layout planning books have many examples of staging yards.  NH Joe

@New Haven Joe posted:

Whether you choose S or O scale, you should consider having a staging yard where you can store trains.  This is especially true for a display type layout where trains are going to run through scenery once and then exit the "stage".  You will need a place to spot your trains for their next run.  There is nothing more frustrating than having to remove a train from a layout every time you want to run a different train.  

Staging yards can be hidden or open.  Many people build a staging yard in an adjacent room.  Layout planning books have many examples of staging yards.  NH Joe

This might be the best advice in this thread. The larger the engine, and particularly so with steam, the more of a PITA they are to move. Just personal opinion here, but in a yard out of sight and dust free is the ideal.

Simon

@AmFlyer posted:

Ok. There is a lot of historical inaccuracy in the Lionel AF road names offered on their engines. I tend to ignore it, mostly because I have not researched or studied what railroads owned what engines.

You're trying to pick apples from a peach tree. Lionel and AF are primarily Toy Train importers, as opposed to Scale Models, although on many of their products, the lines are blurred opposed to what they once were.

Regardless of what  you decide, it would be a wise idea on your part to invest in some reference books on the roads you are interested in so you know what is accurate and what is not, so you can make informed decisions. Good Luck!

Simon

@Jacobpaul81 posted:

Trying to determine space requirements for my needs.  I've got a basement space - roughly 25' x 18' that I'm configuring for the purpose.  I enjoy building benchwork, doing the scenery, running and railfanning.  Not so much operations.  I like the scenic stuff - not a bunch of yards.  Would be 1938-40ish ATSF prototype.  Would like to fit in a round house for a few steam engines.  Thoughts? Advice?

You've managed to set a fair amount of criteria and boundary conditions to define your objectives which is an excellent start.

Would be helpful to maybe see what the actual footprint of the 25' x 18' after being configured for use - access into the space, egress, windows, other "fun" obstructions and obstacles.  Have to remember to allow room for access and aisles, nothing deeper that you can comfortably reach over and across to pick up what might be your heaviest engine, and curves to accommodate the largest engine that you might envision having running with it being able to traverse the track from the roundhouse to the mainline.  Roundhouse will take up a good bit of real estate along with the turntable.   Might start sketching out some plans on the back of the big envelope to see what fits where best.

Despite my misgivings about the lack of options available in S (and the apparent skyrocketing costs), I do think it's probably the best option for my space - so I think I'll stick with that direction. 

Good suggestions so far. I've been taking the same approach on my layout that you are looking to take. I planned  a turntable into my design but have avoided putting it in on purpose. A turntable not only takes up space, but they also usually come with expectations of water towers, coaling towers, at least some yard space and other facilities. It often dominates a layout.

You definitely have the space for whatever engines you need and will be a matter of getting a little creative with the track layout. Have you determined what engines including importers you will have for that 1938-1940 time frame and nailed down what they can negotiate in radius?

I planned for more lower level storage than I needed at the time but now I want more lower level storage which I will be adding. It would have been easier to have added storage tracks in every imaginable place possible from the beginning. In this regard, I think the previous posters are dead on.

As I recall, the OP has done detailed research on the specific location, era and industries he plans to model. I believe the question is how that trackage and location is configured within the available space and what supplemental trackage is appropriate to make a fully functional layout that is fun to operate. 18'x25' is a generous amount of space for an S gauge layout. Mine is in a 17'x21' room. I have a turntable, roundhouse, engine service area and freight yard. The turntable has a 22" bridge and will turn every S scale engine made except Lionel's Big Boy, which as you know started life as a K-Line O gauge engine. The entire roundhouse, turntable, approach tracks, and service structures fit is a space that is 8' long and is 30" wide at the roundhouse, tapering down to 6" wide at the entrance. This is a lot smaller than the O scale equivalent.

There is also a passenger yard. The layout has 700' of total track with a 30"minimum radius. It is possible to fit a lot more full scale items on a layout in S than in O scale. The cost and difficulty of finding the right models is the downside. In too many cases the model does not exist in S.

The concept of a hidden staging yard is great. It facilitates bringing trains onto and off the operating segment of a layout. Visible storage, one engine to a track is needed. I can store 9 engines at the roundhouse and another 7 at other places without stacking them up on a siding. I have found storing 20 engines nose to tail on a hidden track is not practical for me. The engine I wanted was never at an end and after a two days I could not recall the sequence of engines without a constantly updated cheat sheet. My preference has evolved from trying to keep all engines on the layout to just the 15 or so I will use in a week with the rest on off-layout display tracks. I keep complete trains on the hidden staging tracks, each one will hold an engine and about 20 cars.

The comment on access and aisles is also right on. Keep the reach to about 30", depending on the layout height and the minimum aisle width to 30". Access to tracks for cleaning is important. Trying to clean hidden tracks from under the layout is no fun. S scale design turnouts do not like track cleaning cars that slide a pad along the rails. Sooner or later the filed edge of a point rail will pick at the pad and snag. The only cleaning car that works safely is the old Centerline car. I wish I had three or four rather than just one. Most of the track is cleaned by hand.

I look forward to seeing the layout design selected.

@AmFlyer posted:

As I recall, the OP has done detailed research on the specific location, era and industries he plans to model. I believe the question is how that trackage and location is configured within the available space and what supplemental trackage is appropriate to make a fully functional layout that is fun to operate. 18'x25' is a generous amount of space for an S gauge layout. Mine is in a 17'x21' room. I have a turntable, roundhouse, engine service area and freight yard. The turntable has a 22" bridge and will turn every S scale engine made except Lionel's Big Boy, which as you know started life as a K-Line O gauge engine. The entire roundhouse, turntable, approach tracks, and service structures fit is a space that is 8' long and is 30" wide at the roundhouse, tapering down to 6" wide at the entrance. This is a lot smaller than the O scale equivalent.

There is also a passenger yard. The layout has 700' of total track with a 30"minimum radius. It is possible to fit a lot more full scale items on a layout in S than in O scale. The cost and difficulty of finding the right models is the downside. In too many cases the model does not exist in S.

The concept of a hidden staging yard is great. It facilitates bringing trains onto and off the operating segment of a layout. Visible storage, one engine to a track is needed. I can store 9 engines at the roundhouse and another 7 at other places without stacking them up on a siding. I have found storing 20 engines nose to tail on a hidden track is not practical for me. The engine I wanted was never at an end and after a two days I could not recall the sequence of engines without a constantly updated cheat sheet. My preference has evolved from trying to keep all engines on the layout to just the 15 or so I will use in a week with the rest on off-layout display tracks. I keep complete trains on the hidden staging tracks, each one will hold an engine and about 20 cars.

The comment on access and aisles is also right on. Keep the reach to about 30", depending on the layout height and the minimum aisle width to 30". Access to tracks for cleaning is important. Trying to clean hidden tracks from under the layout is no fun. S scale design turnouts do not like track cleaning cars that slide a pad along the rails. Sooner or later the filed edge of a point rail will pick at the pad and snag. The only cleaning car that works safely is the old Centerline car. I wish I had three or four rather than just one. Most of the track is cleaned by hand.

I look forward to seeing the layout design selected.

Right on.  Yes - Historical research is not a problem.  That's how I make my living.

You are correct  - my concerns were primarily related to availability, practicality, and overall cost.  I knew O had the upper hand in availability.  S gauge is just limited in availability - much more available in 2-rail.  Circa 38-40, the steam roster is limited to the 2900 class 4-8-4s, the USRA 4-6-2s (which were originally designed from ATSF 4-6-2s - albeit with a different cab and minor modifications), and Baldwin 2-8-0s which were a generic locomotive for many roads.  The other options are for the late war period - I was off on my dates there - '45-'47 for the Berks and Y3s.   2-rail has all of those and many more motive options including 3700 class Mountains, 3751 class Heavy Mountains (4-8-4), both classes of 4-6-4s, etc.  There was even a run of 50 2-6-2s if you can find one. Plus many other earlier brass runs that I'm not even gonna get into - So 2-rail clearly has the upper-hand on locomotive availabilty.  Also 2-rail far outdoes S in availability in rolling stock (and affordability of rolling stock).  The affordability is a bit of a wash however as used AM locos are generally selling for less than used 2-rail -  but not that much less in many cases.  Also - track is more expensive in 2-rail over S.

So for me, it's gonna come down to practicality in my available space.  I'm pretty sure O is gonna end up being too tight to fit what I want - but we'll see.  I like narrow benchwork and minimalism of non-natural scenery - so if I can make O work, I will - otherwise, I think S has the upper hand.   I've considered HO - and it's just not for me.

Another option is ON30.    Bachman has a laarge line of O Scale rolling stock that runs on HO track.    the track gauge is about 32 inches in O scale.    The stuff is all based on narrow gauge prototypes, and generally smaller ones.    The equipment is all short and rustice and the curves can be down around 24-30 inches I think.    All the scenery and buildings is O scale 1/4 inch to the foot.     Peco makes a line of track that repiicates narrow gauge track tie spacing etc, vs  HO>   Larger O size ties and wider spacing and tie length.   

Also most narrow guage was built and run between about 1870 and 1929 when the depression killed most of the survivors.    The lines tended to be short, rural, and isolated.    Therefore lots of rural scenery.    There were narrow gauge RRs in most states.    Many only lasted a few  years before going bankrupt or being taken over and widened to standard gauge.     However notable survivors were the East Broad Top in PA, the Narrow Gauge stuff Colorado, D&RGW and CS.    Also the Washington and Waynesburg in western PA and the Ohio River and Western that ran from Wheeling to Zanesville in Ohio.    there was a narrow gauge line that ran from around Lebanon Ohio into Cincinnati.     there were the Maine two-footers, and the Tweetsie.   

So lots of choices if that rows  your boat.

Fiddling around with the space.  It could be done.   This is drawn with 52" radius.  Unfortunately I can't layover the grid.  It's a lot of turning.

A possibility thinking back to my first "big" layout in Ohio, You could go through the wall above the freezer and below the electrical box around through the stairs and along the bottom wall.    This could be done with a single track on a 4 inch shelf.    In the Open Area, finish the base board or make it a nice looking shelf so it fits with other furnishings.    You could even put a shelf above it for books or what ever.     Then  you could use the areas in the other part of the basement for more scenic/railroad things like some industrial sidings.    Running around the whole area like that would easily let  you use 52 inch radius.   

Your track plan does not include a passing siding, but I would include one.    I think a good place would be along the long 25 ft wall where the lead to the roundhouse is located.      Then put the roundhouse lead off the siding.    Depending on how long you want it,  you could have it start along the back wall right before the curve and run around to front and end right before the loop back curve.

prrjim,

I was thinking the same thing about going through the wall. If that wall isn't load bearing, I'd do my best to make a full passage and move the refrigerator and freezer.

For my layout I took down a 12' long wall, moved the water heater, and negotiated the trains over a washer and dryer and under a set of stairs.

On my current layout I just have tunnel portals through the walls of the furnace room.    The wals are not load bearing, but it hides the water heater and furnace.    I have the good fortune of having the laundry on the main floor and a wife who does not want a big freezer.

I wrote this in another forum about my research into this issue.  Perhaps it might be helpful to the group.