I'm back ..

Ian - no math this time I promise. Your question begs questions. What railway are you modeling and, if freelanced or proto-based, what did IT do? 

Secondly, what do you enjoy doing with your railroad - and I mean to ask if you are watching trains run over the line, like a bridge route, or building it strictly to runs some trains from staging to ... ? 

If you intend to have industries and run trains (plural) with others perhaps, then always go single track to put a level of thinking into getting safely over the line without a cornfield meet. This can easily happen with DCC or, in my case, battery powered engines.

The fun and challenge of running a train over your line and meeting others cannot be paralleled for fun. Look up Frank Ellison on the "Art of Model Railroading" (or something like that). He makes parallels with the model railroad as a show, a play, where the layout is the stage and the trains the actors with engines the stars! If he doesn't stir the juices the. You might rather railfan.

Neil Erickson

p.s. It turns out that the 1944 article is copyrighted but a free download for MR subscribers. nce

I tend to disagree.  If you

I tend to disagree.  If you are modeling any kind of busy track with multiple trains running at the same time then I strongly suggest duel main lines.  Unless you have working signals and a good dispatcher and crew.

Pretty much anytime you have half a dozen operators or more on a single main it is going to turn into a traffic jam unless you manage to get the design spot on.  Some bottle neck will start to back everything up.  Fast clocks are nice but some things don't scale.  

So if your operators are more casual and easy going then do them and you a favor and go duel track.

If you want to chance back ups and your operators enjoy spending large parts of the operating session sitting and waiting for a chance to move 20' down the line to the next passing siding were they can wait four a real hour or more, then go single track.

But if you go single track make sure that you have two more passing sidings then you will EVER have trains running.  And don't forget to take into account any train that may be running late.  As one late train can fill up the last passing track giving you no place to pass a train so no one can go anywhere.

Now I understand that on the prototype railroads a lot of time was,spent sitting in a siding waiting for another train.  But the prototype engineers get paid for that the model engineers are doing this because it is supposed to be fun.

Also the sidings need to be reasonably evenly spaced.  Or you will get everyone trying to use the same siding at the same time.  On the other hand if all your switching is on one end then you will need more sidings in that area.  And yes I contradicted myself but as noted it is very hard to get the design right so you avoid bottlenecks.  And this is an example of why.  Something that works for one layout can cause huge issues on another.

Of course if you don't plan on operating sessions then you can do whatever you like.

Doug

Actually Neil I understood

Actually Neil I understood the math (I think)  and it helped. Anyway I was really just curious what others preferences were, but anyway my layout is mostly gonna be freelance south eastern  railroad set between the 30s and 50s, lots of freight but coal being the big thing.  I have a lot of Norfolk and Western but I like other railroads too. 

My layout is gonna be roughly 16x20 and will have a large under layout staging that the main goes through via a helix and comes back up another helix.

i like operation and railfaning my layout both, and I will be operating both on my own and with others but more on my own. 

Ive been planning on double track but I thought I'd get some opinions?

thanks Neil 

Doug, you typed out a lot of

Doug, you typed out a lot of my thoughts, I will have a decent layout but not huge and a do want to operate. However I don't plan on having a dispatcher or opperating signals ( at least not in the near future). All that being said I think my plan of double track will be best, I'm planing a long branch line so I'll put passing sidings on that and that'll make for some good operation. 

I wanna run a lot or trains, so I think dual mains will be best. 

1, 2, or 3?

   When I first started out on paper my layout was going to be a three track mainline with one track to be an express track with only one or two stops. After some careful thought I decided that the third track was a waste of time to build, served no useful purpose and away it went. This opened up room for sidings but none of them passing ones. One track has a steeper % grade than the other as one is east bound and the other west bound. Steeper grade on the down hill of course. If I had made it a one track mainline with passing sidings, operations would be a rats nest of confusion. My advice is go two track mainline. Take the advice for what it's worth, just my experience. Good luck however you decide and keep us updated.

Yes three or more tracks is

Yes three or more tracks is to much at least for me. I am gonna make it a double main. And I'll post my progress!

Depends

By your question I am assuming you are not building a prototypical layout.  (Specific place, time, etc...)

Personally I like single track operation with passing and/or industrial sidings.  Offers more operational fun and challenges!  

One thing I would recommend is to plan your siding lengths to accommodate the longest train you plan to run.  

Joe 

More to consider

I prefer single track, both for the operational challenges and the appearance.  I've read before, and agree, that double track, with a wider ROW, tends to make the distance between two points look shorter.  Something to consider on our already-too-short layout designs.

Yes, double track may be the way to go if what you enjoy is to get trains from one staging yard to another, or between a visible yard and staging, as quickly and efficiently as possible.  However, my experience has been that that can get boring quickly.  On my single-track layout, train volume is so low that meets are rare (much like double-track), and operators have expressed that they look forward to when they do occur.  If you find that operators are sitting at meets for extended periods, as was mentioned above, it may be that you're simply trying to cram too much into your layout operationally.

Keep in mind, also, that a layout that's busy enough to justify a double-track main, besides soaking up more money and time for track, will require more rolling stock and locomotives, which in turn require more money, build time, and maintenance.  In the 1930s-50s era you mentioned, steam would be a big factor, and from what I've read, the time and effort to keep a model steam locomotive running well is significantly more than a diesel.  Just some other things you might want to consider before you dive in.  I speak from experience when I say that it can be VERY easy to bite off more than you can chew with a layout, causing it to become more of a burden than a hobby, when many of us have found that we enjoy something simpler and easier to maintain that, in turn, also keeps costs down.  Less truly can be more.  

Before deciding on your design, I'd strongly suggest operating on a variety of layouts if you have that opportunity locally.  Find out what you truly enjoy before you jump in, and I believe you'll save yourself a lot of money and frustration.  You may confirm that a big, busy double-track scenario is just the thing for you, or you may find, as I did, that something more easy-going is more your style.  There's no right or wrong answer, but having more experience with a variety of layouts will certainly help you make the best choice for you.

Main with passing sidings

I am a "lone wolf" operator who runs sequenced switching. As such, I never run more than one train at a time, so I went with a main with many passing sidings, industry sidings and spurs. I run a train out of staging, do some switching and run it back or to the staging on the other end of the layout. If I don't complete the switching, I leave it parked on a passing siding until I come back to finish the sequence. Then I repeat with another train; different train, different industries. If I want to run a through freight, the main is clear from end to end, 165'. Considering the expense of the additional turnouts versus the extra track, I actually probably came out ahead because I would have needed some crossovers anyway.

If like Doug, you have multiple operators, then a double main would probably serve you better. If your staging allows for continuous running, then you could run a train on one main while doing switching on the other. I myself do not relish the idea of running two trains at the same time by myself. If you have a fellow operator then it would be easier. 

My thoughts only, it's your railroad.

Willie

Both?

I model a class one railway on a fictitious line and have both double and single track. This makes operation sessions more challenging and allows me to have a couple trains running on their own while I time mine to duck and cover.  Not everyone's cup o' tea but I enjoy it. 

Those are good things to

Those are good things to consider, You've given me something to think about. This is my forth layout technically but I didn't finish the others cause they turned out to have to many problems. But all of them were double track and I liked it but I dunno, I'll at least have to consider single.

Double vs Two vs Single track

There is actually a prototype railroad difference between "double track" and "two main tracks".  If you are interested it can be discussed.

The positive side is having dual main tracks allows you to run a lot of trains.  The down side of dual main tracks is it allows you to run a lot of trains.  On a dual main track will burn through a lot of trains quickly.  That means each operator spends less time actually running a train, you will need more physical trains, you will need more staging, you will need more cars.  On a shorter run (the main track less than 4 train lengths long) if you stop one train on line to do switching it will cut the capacity of the railroad in about half.

Dave, what is the difference

Dave, what is the difference between two main tracks and double track?

Layout size has a lot to do

Layout size has a lot to do with single and double track. 16 x 20 is not a huge space where larger sidings can be spaced apart a great deal. I would suggest two tracks with frequent cross overs that would allow passes if you wanted. A switcher could work industries and if you have up to three trains running you could get them past each other. It would also have less effect on making things look to small.

I have a double track main and...

I have a double track main layout with numerous crossovers along with a couple of secondary sidings. Signals are controlled by the dispatcher, and rarely do we have train meet issues. As long as everyone pays attention (which they do for the most part), my freelanced fictitious, congested layout runs very well and our operating sessions are fun and enjoyable.

Neal

Double vs Two Main tracks

 The difference is how they are operated.

Double track is typically Rule 251 or Rule 9.15 (GCOR) and is commonly called "current of traffic".  One main is for eastward traffic and the other is for westward traffic.  If they are signalled, they are signalled in one direction, with the current of traffic.  Movement against the current of traffic is movement in unsignalled territory (dark) because the track has no signals in that direction.  The benefits are that movement with the current of traffic is very easy.  the train gets on the track in the proper direction and with minimal paperwork (typically a numbered clearance) goes.  The hard part is if the train has to cross over and run against the current of traffic.  That typically requires train orders and since the train is moving in  dark territory the speeds are reduced (on a 70+ mph railroad, the trains are limited to 49 mph against the flow.)  Industry switches and crossovers are mostly trailing point and manually controlled by the train crews (except at interlockings where the control operator handles them).

Two main tracks have the trains operating in both directions on both tracks and if the tracks are signaled, they are both signaled in both train directions.  CTC is typically two main track territory.

If you model double track it simplifies trains running, but in some ways complicates trains switching.  CTC is more complicated for a signaling and switch control/wiring standpoint but is probably the most flexible system.

From about 1900 to the 1970's double track was the most common way to operate multiple main track territories.

Layout size

I figure that a running foot of HO main with 2 ft benches and a 4 ft aisle, takes up 4 sq ft. 16x20 = 320 sq ft, which translates to about 80 ft of single level, once through the scene main track.    My last layout was 12x23, very similar in size.

Figure a train is about 15 cars or 10 ft.    A yard is two to three train lengths long so that's 20-30 ft.  That leaves 50-60 ft of main line run, figure about 3 sidings or sets of crossovers out on line.

Long term interest

Lots of good history and arguments both ways here. In particular the idea that a double track mainline will take twice the amount of track, probably no less switches, and a ton of cars and engines unless reused throughout operations. No argument that this has it's appeal but I will throw this out one more time as it was so influential to my choices along the way. This is an excerpt from Part 2 but the first four are worth reading again.

Neil

I tend to disagree.  If you

D&RGW had a single track mainline, and while maybe not as busy as some, if you watch Rio Grande Odyssey DVD, Rio Grande earned it's name The Action Road because it has short fast frequent trains rushing across the system to compete with the UP to the north.  Just sayin...

That's very intresting Dave,

That's very intresting Dave, I didn't know the difference between to mains and double track, thanks for the info!

Personally...

...I prefer single track as I find the operations much more interesting. I have operated on many, many layouts over the years and the vast majority were single track. The few I have operated that were double track tended to be "race tracks" that just ran trains.

One exception was a Great Western Railway (British) OO scale layout that was in a double length garage. It had a large fiddle (staging) yard on one side that held about 20 trains and the other a small station with just 3 turnouts, a crossing and two platforms. The station was a good duplicate of the prototype and we operated the whole railway with a the correct types of trains that ran through there in 1935. It took 5 operators 2 Drivers, Yard Master, Station Master and Train Controller (Owner of layout and overall boss!). An Scale 8 hour session was about 30 trains. Bell control (Simple Telegraph used by a lot of British and British built Rwys) and semaphore signals controlled movement. It was great fun and very intense.

My thoughts on all this is "it is your layout" so you can do what you want but if you do end up with ops session then you either need a massive staging area or run the same train several times.

Maybe an alternative is half and half. Model the end of a 2 track division going down to single track?

I was talking about model

I was talking about model railroad not prototype.

On a model railroad, and I have operated on a lot of them, invariably what happens is one or more trains gets delayed a bit, perhaps taking longer to do some switching.  This means that there is one more trains on the railroad taking up additional passing sidings.  So now there is less (or no) places to pass trains and the operating session turns into that kids game with the numbers and one open space were you have to get the numbers to line up.

You spend all your time waiting for an opening to move your train to.

The prototype does not have these issues for a few reasons (well usually they don't).  First off they have a lot longer distance between passing sidings.  Also a delay of 10 or 15 minutes in switching is not a big deal in the prototype but in a model it is huge.  The prototype also has more passing sidings per train. So it takes a lot more trains to cause a traffic jam.  On top of this the prototype folks have a lot more experience running a railroad.  Plus there railroad has had decades or more to iron out the bumps.  And let's not forget that they don't care if there crews are having fun, they pay them so if they get board to bad.

Now if you have a lot more passing sidings then you will ever run trains... then more power to you. But most layouts only have a hand full of sidings

Assuming a 500 sq ft layout, you would be lucky to have 250' mainline.  Assuming 20' needed for a siding counting turnouts and separation distance.  And assuming twice that distance between passing sidings and you get one siding per 60'.  Or about 4 sidings.  Needing one of these to be empty at all times and you can run two or maybe three trains.  Even cutting back to one siding per 40' gives you a max of 6 and that doesn't consider yard space.

So if you want to run more then a couple trains and don't want a huge traffic jam then you needlarge layout or you are going to have the passing sidings so close to each other that you may as well have a double track mainline.

-Doug

Mine is kind of a hybrid.  I

Mine is kind of a hybrid.  I have a double main line but they only connect to each other at the main yard.  I can start one train going around the room and switch the other main along the route.  Almost like having two single main lines.

Steve

" my layout is mostly gonna

  Single or double track  would depend on what location in that SE area you choose to model. Choose the setting first then the track needed will become obvious. It's quite possible that both would be a good choice, a double tracked segment of busy mainline with a single tracked branch up into the hills perhaps? .....DaveB