Long Mainlines....Are They Important?

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Section Hand
My layout is of a modest size and often though that if I could, I would extend the mainline for longer runs since I like watching trains run. But like Chet, I do a lot of switching. I have had a change of mind since recently attending a Train show. One mod layout had a mainline of approximately of over 100 feet and I stood there for several minutes and watched the trains passing by me.

Well as I watched the trains circle the mod layout even given having a long mainline, sooner or later the mainline seemed shorter just like mine at home. No matter how long the mainline is...the reality is facing the fact that our layout's track plan may only be a circle of track running through the scenery no matter the length and sooner than later the train returns after passing by.

Maybe the length of a mainline is all relative and not the most essential part of a successfully planned layout.

Next time I'll run a short train on the mainline while I perform switching. Often stopping the mainline train for the local and the locals for the mainline. Try to keep it interesting.

What are you thoughts on the importance of long mainlines to keep up interest and for train watching?


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Whiskey Merchant
Although my train room could have had more of a main line run, I chose to only have the track pass through any area only once instead of having the track loop over and around itself, leaving more room for towns and scenery. The room is 24' x 17'. With the use of hidden staging tracks I can run long trains. I have exceeded the 100 car mark, with the train being in three towns at the same time.

With a two and a half percent grade, that took a bit of doing with three locomotives at the head end, one in the middle and one pushing at the rear. T

The grade helped me determine the length of a local freight train, which works out to be around 14 cars which is the length that my passing sidings can handle. A normal local train is around 10 cars. I am happy with trains of that length and if I want to run long trains, I can always do that at the club.

Even with the chance to run long trains at the club, I usually only run a train of around 10 cars which is the limit of what my locomotives can pull on the clubs grades, but makes things interesting having to take a passing siding for long trains.


Active Member
It depends on what you want to do with it.

If you want to focus on industrial switching operations, maybe not.
If you want to focus on yard switching operations, maybe not.
If you want to railfan long trains, then maybe you want a bit of a longer run for them to feel at home in and it's not chasing 3 cars behind its own tail.
If you want to model train operations and dispatching, then you definitely need some running room and sidings long enough to pass trains.


Well-Known Member
I do have what many would consider a long mainline with 165' on each of two unconnected levels (helix in the future). However I do not have a continuous run option as they are both point to point. There is no place on my layout where the train runs through the same scene twice. I like switching primarily and I have multiple passing sidings with lots of switching, currently 35+ industries on each level, as yet unfinished so more to come. I normally run a local out of staging and sometimes pause on a siding while I go back and run a through freight from end to end; then I go back and complete the local switching run. I may do this multiple times in a session since I am a lone operator. I am not a fan of unattended train running no matter how good one's trackwork is. Due to backdrops and a serpentine layout, the maximum that I can view from any location in my layout room is about 25%, thus the need for a walk-around memory throttle. Because of the number of towns and switching locations, my mainline never seems too short even though there are some places where a 24 car through freight can be in two towns at once. But I normally can't see this because 24 cars is too long for me to see all at once anyway, peripheral vision or something like that. 32"-34" aisles prevent me from standing back any further. At a train show, aisles are not a restricting factor and you can see much more of a train than on many home layouts. That can certainly be a restriction on home layouts where space is usually at a premium, or we try to cram all we can into too small an area. Something to consider.
That being said, I do not in any way disdain continuous run layouts. I grew up with my father's continuous run Lionel layout with seven trains running simultaneously (fuse box humming due to the two ZW transformers), which got me interested in model railroading to begin with. One of my brothers has a 13' x 20' continuous run HO layout which I enjoy seeing. Another brother continues the Christmas only loops with my dad's stuff. That one is particularly nostalgic for me. I can still watch it for hours.


Loveably weird
My mainline is about 24 feet long, around the room. I'll have a train doing the roundy-round while working in the yard or switching the industries. I'd love to have a nice long mainline, but it is what it is.


Well-Known Member
Staff member
I prefer longer mainlines for the sole reason of being able to run longer trains without them seeming out of place or looking as though they are chasing themselves.

Bear in mind I am N Scale but one lap of one of my Double Mainline Tracks is 44.5'. All up though, I have 130' of mainline not including sidings and spurs. For me, it's all about sitting back and watching the trains run and NOT passing themselves every few seconds. So yep, I'd say, in my situation, long mainlines are an absolute necessity.

That being said, and for those who do like long runs, I don't think ANY run of mainline is "long enough" :)


Active Member
Depends on what the goals are and what you consider "long". I tried to get the longest run I could, but didn't do anything like looping through scenes twice to make a longer run. I don't have a "circle of track" (well technically in about 4 years when I complete the next section, I will have the ability to continuous run) . Its point to point, when operated I use TT&TO. The layout currently has a 72+ ft main and about 1/2 the layout is built, it will have about 130-140 ft when done. For my layout a big train is 16 cars, about 8-9 ft long, a typical train is about 10 cars, less than 6 ft long. I have about 1.5-2 train lengths between sidings.

new guy

Active Member
Planning for the space I have and what I now know I can do vs what I want to do I'm going to have about 15 feet of storage yard with maybe six tracks just for "off duty" parking and at least 110 feet of main. Plus sidings and at least one more yard. 500 sq feet of table to fill. HO scale. I'm gonna try to "have it all" LOL Had a four track main all around but it takes up too much room may go with just a double, love to "race" em!

D&J RailRoad

Professor of HO
Ya really do need a long mainline for your trains to stretch their legs and run. Adds distance between service points. Go for all the room you can from the home space manager and then push those limits as much as you can. You can usually get three expansion approvals before the threats to cancel all your space comes up.


Well-Known Member
If you like to watch the trains run, a longer double track mainline might be better. Some people like to do switching in a given area, while the 'mainline train' goes around and around. My only comment is that at some point, the larger the layout, the more need for maintenance.


Only if they are important to the modler.

If important, the modeler should make the mainline as long as they can, given the size of the area they have available, if that aspect is important to them. My main is about 135 feet long, it is a loop that wraps itself around the layout three times. To me, at this time in my enjoyment of model railroading, 30 years in the process, I don't feel mainline length is as important as the industries and locations to serve along the main's length. These locations are what give the RR it's jobs to get done in an operating session.
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