Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Double vs Single Track Mainline in HO

2079 views
32 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    June 2003
  • From: Ponte Vedra, FL USA
  • 112 posts
Double vs Single Track Mainline in HO
Posted by mrnimble on Monday, July 18, 2022 5:06 PM

I am presently tinkering around with a design (AnyRail) for a new layout and am not sure about reality vs what looks good on paper.  Basically, am I trying to cram too much railroad into too little space?  (Serious downsizing took place in this retirement move).

Space limitations have me pretty well restricted to a classic dogbone footprint with 4' x 8' islands, or bumps, at both ends and a 16' x 20" deep shelf along a wall connecting the two.  I would like to double track the mainline which would converge at each end into a single track reverse loop for continuous running.  In between I want to include a crossover and a couple of passing sidings.

Salvaged items from a previous layout consist of several industries, a 5 structure town, a passenger station, and a 2 bay engine repair shop.  So I'm good to go with a start on scenery.

Meanwhile, any insight as to the practicallity of a double track mainline taking away from the available space for scenery and switching will be helpful.  Thanks.

  • Member since
    September 2003
  • From: Southeast Texas
  • 5,355 posts
Posted by mobilman44 on Monday, July 18, 2022 5:54 PM

Double track mains are pretty impressive, especially when running heavy traffic.  But, when you are pressed for space, crowding in that second main may take away so many other layout possibilities (i.e. industries, sidings, special scenery, etc.).

For what you are describing, perhaps a passing siding might be a good substitute, or maybe the space could be used for a secondary track - not in line with the original main.  

No way am I knocking a double main, but they come at a cost.

In the end, you may want to just lay your track on the benchwork and fiddle around with alternatives.  Software and scale drawings are really great tools, but nothing compares with just placing the track on the ol 4x8s........

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,147 posts
Posted by selector on Monday, July 18, 2022 7:14 PM

First two layouts were single mains.  They worked nicely, but I'm not an ops guy.  I like main line running, some switching for variety, some maintenance in bays (in transition era, that means a turntable and roundhouse, a large machine shop, etc).

Second two layouts, including what I'm running now, are doubled mains.  Very nice...if you have the room....AND...AND...the curves you would really love to have, or close, will fit, both inside and outside mains.  Ask Sheldon how much he insists on wide curves, and why.  Once you knuckle under and build 'em, there's nothing like 'em.

With that aside, you'll need at least one crossover set/double crossover.  Two would be better, and get them as close to your yard throat(s) as you can, say within about four feet.

I don't really agree, based on my own limited experience, that a double main necessarily impacts on scenery space, although it certainly would if the room and benchwork are necessarily small.  My space is much like yours, but I go around the room with a duck-under entrance.  I have to stand in the middle and pivot as the trains circle around me...which is precisely what I prefer because the backdrop is always outboard and I needn't move along with the trains to appreciate the backdrop.  I just pivot.

Once again, twinned mains are really neat for passing trains, even with trackage rights between two roads, or a pax train gaining on a coal drag and roaring past going in the same direction. Or passing going the opposite direction...it all works and is a lot of fun.  And they needn't take up scads of room, especially on 2.5" centers.  Most benches will be near 24" deep anyway...some a lot more.  

Don't forget the crossover!

  • Member since
    June 2008
  • 49 posts
Posted by PennsyLou on Monday, July 18, 2022 10:01 PM

For railfanning I'd definitely go double track - the space you have is large enough that you could easily have two trains running "half a loop" away from one another resulting in plenty of traffic through the central town.  I'm constructing a layout based on the PRR with a double track main with a maximum bench width of 20-21", and I'm finding that there is plenty of room for scenery, sidings, etc. - anything much deeper than that starts to have reach-in issues anyway.

  • Member since
    September 2003
  • From: Omaha, NE
  • 10,325 posts
Posted by dehusman on Monday, July 18, 2022 10:21 PM

ARe you looking at a double track loop, two tracks that go all the way around, or are you looking at a dogbone, a loop where the middle has the two tracks right next to each other between the ends.

Major difference in complexity.  With the true double track loop you can run trains in both directions and they can crossover between the two mains anywhere they want.

With the dogbone, all the trains orbit in the same direction, but in the middle it looks like they are going in both directions.  If you cross trains over in the "double track portion", that has to be treated as a reversing section and has to have reversing switches (DC) or an auto reverser (DCC).

Dave H. Painted side goes up. My website : wnbranch.com

  • Member since
    April 2021
  • 15 posts
Posted by wvgca on Tuesday, July 19, 2022 7:46 AM

i made my layout [16' x 20'] a double line ... it was nice to set locos out and just railfan ... no worries about them hitting each other if all the turnouts were set correctly ..

  • Member since
    September 2004
  • From: Dearborn Station
  • 22,938 posts
Posted by richhotrain on Tuesday, July 19, 2022 8:15 AM

Over the past 18+ years, I have built 4 different layouts, all with double mainlines. Since double mainlines with crossovers can be constructed with parallel mainlines with 2” on-center alignments, that second mainline takes up very little space, leaving plenty of room for structures and scenery even on a 20” width of subroadbed.

You indicate that the two end loops of the proposed layout will be set on 4’ x 8’ subroadbed. The one issue that I see with these dimensions is that the curves will be limited to 22” radius after leaving a 2” clearance on each side of the curves. While 22” radius curves can handle short wheelbase steam engines and 4-axle diesels fairly well, if you could add one foot to that 4’ width, the resulting 60” width would accommodate 28” radius curves, sufficient to run longer wheelbase steam engines and 6-axle diesels.

Will your layout be DC or DCC? If it will be DCC, you can use auto-reversers to control the end loops so that the 16’ straight portion of double mainline can be wired the same way despite the fact that crossovers will be used.

I went a step further on my current layout by using crossovers and double slips to maintain the double mainline all around the entire layout. That way, the outer mainline always runs trains in one direction and the inner mainline always runs trains in the opposite direct. In effect, that straight portion of track between the two end loops gives an appearance of a 4-track mainline, but with the ability to change tracks and direction at the same time. This configuration easily fits on a 20” wide section of subroadbed. In fact, there would still be room for a passing siding or two.

Rich

Alton Junction

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 15,940 posts
Posted by SeeYou190 on Tuesday, July 19, 2022 8:25 AM

Two of my layouts have been double tracked, Two were single, and One was just a switching layout. The next will be double tracked.

Like everything else, I just don't have a real solid opinion. I think single track looks better in photographs, but I like to watch trains on double tracks.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

  • Member since
    July 2006
  • From: west coast
  • 7,117 posts
Posted by rrebell on Tuesday, July 19, 2022 9:05 AM

What era and type of railroad? With your situation I would go single and double on some of the connecting shelf, maybe with a vering off or two for the look of a single, but then I model the 1930's. If you model modern, you proubly should do double for most of the mainline.

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 12,890 posts
Posted by wjstix on Tuesday, July 19, 2022 9:15 AM

Well the layout I'm building is sorta-kinda like what you're describing. It's primarily built on 16" wide shelfs, but widens out at each end to form 'blobs' to allow the track to bend back on itself for continous running. However in my case, I was able to add the 4' to the 16" so was able to use 28" radius for the curves. If you only have the 4', 22"R is the biggest you can do - which could restrict you from some passenger cars and engines that need larger curves.

My layout is a dogbone, so the part just on the shelves has the track right next to each other simulating a double-track mainline. At each "blob", I worked in a couple of mainline turnouts so that each blob can work as a reverse loop. I don't think the double-track section takes up too much space, but it's pretty much just running through scenery, the layout structures are in the blobs.

Stix
  • Member since
    July 2006
  • From: Sebring FL
  • 833 posts
Posted by floridaflyer on Tuesday, July 19, 2022 9:44 AM

I'm a fan of double main lines, but agree with stix and rich, the radius of the inner track on the 4x8 sections would be a controlling factor as to types of locos, and passanger cars, that could be run.

  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
  • 11,166 posts
Posted by dknelson on Tuesday, July 19, 2022 11:29 AM

My layout is double tracked because my prototype was double track (and strictly current of traffic so one track was west bound the other east bound, rarely, practically never, would a train operate against the current of traffic).  Passing sidings were few and far between because they just were not needed.   If I was to do the same track plan in single track then of course I'd want passing sidings but ironically that would actually decrease some local switching opportunities because right now industrial spurs come off both main lines, but you don't really want an industrial spur coming off a passing track.  So my lineside industries would be crammed in where the passing sidings ain't, which would change the look and feel of the layout way too much for my taste.  

In that sense I am not so sure double track mains are as much of a space waste as some might suspect.  They open up more freedom for location of rail served business along the main.  

Because there was a fair amount of high speed passenger train activity that I want to replicate, but also mainline freight and lots of local switching, that is another reason why single track with passing sidings would not really work well for me.  

Even if I was not following the prototype's track plan, the types of trains and their frequency I want, and the importance to me of local switching versus arranging the intricacy of meets and passes, all mean double track makes sense for me.  Having said that I had the room so my curves are 42" and 40" radius so I can maintain the 2" spacing of the tangents.  If the curves were really tight maybe I'd think differently, or run the layout differently.

Dave Nelson

  • Member since
    January 2010
  • 159 posts
Posted by nycmodel on Tuesday, July 19, 2022 2:25 PM

My original layout was single tracked with passing sidings and was operations based. The present layout is much simpler and has a double track mainline around the walls shelf style. Great for just running and relaxing. You can't beat 2 trains passing each other in opposite directions. I model the NY Central so a double track mainline is prototypical, more or less depending on the location.

  • Member since
    September 2014
  • From: 10,430’ (3,179 m)
  • 1,869 posts
Posted by jjdamnit on Tuesday, July 19, 2022 2:40 PM

Hello All,

mrnimble
...dogbone footprint with 4' x 8' islands, or bumps, at both ends and a 16' x 20" deep shelf along a wall connecting the two.

How you place the 4'x8' islands (wings) relative to the 16'x20" shelf makes a difference.

Without clarification I see many possible footprints:

  • The 4'x8' wings attach to the 16'x20" (1'8") shelf on the 4' edge making essentially a U measuring 16'x9'8".
  • The 8' edge of the island butts up against the 1'8" shelf making a 24'x8' U.
  • The 4' edge of the island butts up against the 16' shelf making a 32'x4' dogbone.
  • In the second and third arrangements above, turning one 4'x8' island in the opposite orientation changes the overall dimensions again. 

No matter which edge of the 4'x8' islands you butt up to the shelf, the shelf itself is deep enough (1'8") to run four (4) parallel tracks; two (2) in each direction, with crossovers and sidings, is possible. 

Now, how you use the space on the wings for track is a different subject.

An outline of your footprint would help.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
    January 2019
  • 1,922 posts
Posted by John-NYBW on Tuesday, July 19, 2022 3:10 PM

My layout is an around the walls, double track dogbone that fills a 46' X 26' rectangular basement. The end loops are triple tracked staging yards with each track in the loops able to hold several trains. If you want your trains to run back and forth without having to turn the trains the hard way, a dogbone is the way to go. You will need a reversing section at each end. Make sure your loops have a large enough radius to handle your longest equipment. I made my inner loops with just a 32" radius and I'm finding that some of my full length passenger cars won't negotiate that. If I had it to do over again, I would make the inner loops 36". I might actually be doing them over again. I stacked the loops in one corner to save space but didn't create enough vertical separation to have easy access to the lower loop. Combined with the too frequent derailments with the longer passenger cars, it is a nightmare. I have finally had enough and am considering several options to rebuild one or both loops. 

  • Member since
    June 2007
  • 8,707 posts
Posted by riogrande5761 on Tuesday, July 19, 2022 7:19 PM

So John, those passenger cars that could not handle 32" curves, what was the minimum they could handle?

 

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    January 2019
  • 1,922 posts
Posted by John-NYBW on Wednesday, July 20, 2022 5:19 AM

riogrande5761

So John, those passenger cars that could not handle 32" curves, what was the minimum they could handle?

 

 

They did better on 34" radius but 36" was better. The problem with a loop is that the outer loop will have the tightest radius at the throat. That is where many of the derailments seem to occur. I probably should have lengthened the loop but I needed it to stop two feet short of the wall to have access to the house electrical panel. One of the options I am looking at is to see if I can take the loop all the way to the wall with an angled bench and see if that allows enough room for access to the panel. I have to work out the geometry on paper to see if that will work.

  • Member since
    September 2004
  • From: Dearborn Station
  • 22,938 posts
Posted by richhotrain on Wednesday, July 20, 2022 6:58 AM

We have been down this road before. There is no question that Walthers passenger cars often exhibit issues out of the box. But these issues are fixable and have been well documented in other threads. I have 43 of the Walthers full size passenger cars on my layout, and all perform flawlessly on my 30" and 32" radius curves. Some of these cars required adjustments and modifications to perform flawlessly, but I have never had a car that could not be fixed.

Rich

Alton Junction

  • Member since
    January 2009
  • From: Maryland
  • 11,774 posts
Posted by ATLANTIC CENTRAL on Wednesday, July 20, 2022 7:46 AM

To the OP's question,  I would go double track. But it sound like maybe the OP actually has a space 12 x 24? If so, I would go around the perimeter of that space, and view the layout from inside the loop, using a duck under or lift out, again with double track.

As for passenger cars, I have an idea, if you don't have room for large enough curves, don't run 85' cars. My new layout will have all 36" radius and above(mostly above) and I still prefer the more graceful look of shorter passenger cars nicely close coupled.

So back to the layout idea, if we must run long cars on sharp curves, they look better viewed from inside the curve.....

Sheldon

    

  • Member since
    January 2019
  • 1,922 posts
Posted by John-NYBW on Wednesday, July 20, 2022 11:34 AM

richhotrain

We have been down this road before. There is no question that Walthers passenger cars often exhibit issues out of the box. But these issues are fixable and have been well documented in other threads. I have 43 of the Walthers full size passenger cars on my layout, and all perform flawlessly on my 30" and 32" radius curves. Some of these cars required adjustments and modifications to perform flawlessly, but I have never had a car that could not be fixed.

Rich

 

It's ridiculous that a customer should be expected to fix something that is right out of the box. If it needs fixing, it's a piece of junk. Better to not buy the junk to begin with. 

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 20,554 posts
Posted by MisterBeasley on Wednesday, July 20, 2022 11:49 AM

I tried designing a double-track mainline, but eventually went with single track for space reasons.  In the end, I realized I really got more out of the single-track layout, railroading-wise.  Passing sidings became important, not just decorative, and I was able to design a plan with two opposing reverse loops so I could easily reverse trains in either direction.  Yes, I could run two trains going in opposite directions, passing each other every time around.  I could do that for a half hour or so before I got tired of throwing turnouts.

It takes an iron man to play with a toy iron horse. 

  • Member since
    September 2004
  • From: Dearborn Station
  • 22,938 posts
Posted by richhotrain on Wednesday, July 20, 2022 11:53 AM

John, I totally agree with you. It is ridiculous. But, speaking for myself, I bought a lot of these cars as NOS after their production was discontinued by Walthers. So, the only answer for me was to fix the flaws or do without the cars. And, apparently, that was the most viable option for many other forum members as well as the discussion several threads has proven.

The one comment that you made that I take issue with is that the Walthers passenger cars only perform flawlessly    on radius curves of 34" or greater. In my experience, these cars perform flawlessly on 30" and 32" radius curves as well.

Rich

Alton Junction

  • Member since
    January 2019
  • 1,922 posts
Posted by John-NYBW on Wednesday, July 20, 2022 1:28 PM

richhotrain

John, I totally agree with you. It is ridiculous. But, speaking for myself, I bought a lot of these cars as NOS after their production was discontinued by Walthers. So, the only answer for me was to fix the flaws or do without the cars. And, apparently, that was the most viable option for many other forum members as well as the discussion several threads has proven.

The one comment that you made that I take issue with is that the Walthers passenger cars only perform flawlessly    on radius curves of 34" or greater. In my experience, these cars perform flawlessly on 30" and 32" radius curves as well.

Rich

 

It speaks volumes that you immediately knew I was speaking about Walthers passenger cars when I didn't even mention the brand in my reply to the OP. 

  • Member since
    September 2004
  • From: Dearborn Station
  • 22,938 posts
Posted by richhotrain on Wednesday, July 20, 2022 1:32 PM

John, you have indicated that Walthers is the culprit in several threads.

Rich

Alton Junction

  • Member since
    January 2019
  • 1,922 posts
Posted by John-NYBW on Wednesday, July 20, 2022 2:39 PM

richhotrain

John, you have indicated that Walthers is the culprit in several threads.

Rich

 

My comments weren't even directed at the faulty cars. I was speaking of the flaws in the design of my reverse loops. I didn't even mention the quality of the cars involved. 

  • Member since
    September 2004
  • From: Dearborn Station
  • 22,938 posts
Posted by richhotrain on Wednesday, July 20, 2022 2:48 PM

OK, sorry, I only meant to follow up on riogrande's question and your initial response to it.

Rich

Alton Junction

  • Member since
    June 2007
  • 8,707 posts
Posted by riogrande5761 on Wednesday, July 20, 2022 3:14 PM

John-NYBW

It's ridiculous that a customer should be expected to fix something that is right out of the box. If it needs fixing, it's a piece of junk. Better to not buy the junk to begin with.

 

While that may be true, if you want to build a passenger train of a certain type and can't afford brass, then you either buy and fix the cars or go without.  I can't afford brass, or much of it, so i"ll be using the Walthers cars rather than go without.

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    July 2006
  • From: west coast
  • 7,117 posts
Posted by rrebell on Thursday, July 21, 2022 10:15 AM

riogrande5761

 

 
John-NYBW

It's ridiculous that a customer should be expected to fix something that is right out of the box. If it needs fixing, it's a piece of junk. Better to not buy the junk to begin with.

 

 

While that may be true, if you want to build a passenger train of a certain type and can't afford brass, then you either buy and fix the cars or go without.  I can't afford brass, or much of it, so i"ll be using the Walthers cars rather than go without.

 

Also some times the flaw is so minor, it is worth fixing. Had a frieght car once that needed a very minor piece of detail removed so the wheels would turn on one end, design flaw to be sure but could be fixed in a second.

  • Member since
    June 2007
  • 8,707 posts
Posted by riogrande5761 on Thursday, July 21, 2022 1:50 PM

For the Walthers cars that have issues on 32-inch curves, what was done to fix the issue?  Was it due to how closely they were coupled or was it an issue with trucks and the underbodies?

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    February 2008
  • 7,979 posts
Posted by maxman on Thursday, July 21, 2022 2:23 PM

I thought this thread was about single vs double track main lines.

Why must you characters drag in all the non-related stuff? 

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!