for an ho scale modular layout, is it better to have the tracks connect with a short span, or rails but up to the module edges? do you use an alignment pin outside of the track? C clamps to hold modules together?
All of those are used by various "systems" and all can be successful. Which one is "better" depends on how well you can assemble your modules and how much precision you build in.
Dave H. Painted side goes up. My website : wnbranch.com
It realy depends on the reason to be modular, are they to be moved alot or is this just in case of a move.
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
The 2 methods commonly used by modular groups are fitter tracks and butt joints. Both these methods assume having to join modules in almost any order at shows, have reliable operation, and setup and takedown be fairly quick.
The fitter tracks in general allow for more misalignment - each joint takes about 1/2 the misalignment. The reality is that seldom are fitter tracks exactly the same length between any 2 modules, and exactly what are needed for the next show in a different venue. Because of the variances, most Free-mo setups ended up needing a variety of connecting piece lengths. This tends to slow the setup process down.
Butt joints, as illustrated by Bear, are generally faster to set up IF the modules being joined are close enough to spec. The downside of butt joints is in transporting the modules - it is quite easy for the rail end to catch on something and rip the rail/track from the end of the module. And the module end specs need to be tightly controlled.
My preference is for butt joints with a storage rack/box for transport that protects the module ends.
In either case, aligning modules during setup takes critical eyes, and not settling for "good". Alignment can be done through alignment pins - which add yet another accuracy-critical component to the module build and another hassle for transport - or through adjustable legs and clamps - which requires skilled eyes and fingers. Top adjustable legs - where the leg length is adjusted by rotating the leg at the top instead of at the bottom - make the clamping system a lot easier to put up with.
The HOn3 modular club I was with went from fitter rails to butt joints. Clamping is used at the end plates, top adjustable legs are mandated. It is a very fast setup that can be done with 1-2 people provided the modules are short and light enough.
The Sipping & Switching Societies (S&SS) go the opposite direction with tapered 1" pipe for alignment pins. Legs are non-adjustable, which means legs may or may not touch the floor. Their modules are very strong, and they typically use longer modules with carts to transport them. S&SS also has a very short setup time.
just my experiences
Fred W
....modeling foggy coastal Oregon in HO and HOn3, where it's always 1900....
So far no one has mention an important distinction: Modular and sectional.
Modular, such as freemo, means that anyones mods, buikt to spec can be set up in any order. So you must use their specs for everything.
Sectional means a portable layout always set up in the same order. The group doing it sets all parameters. Our club has a sectional layout. Butt joints with plywood ends for storage. The centre section on each side has four legs, all others have two. The sections are joined by door hinges. Buildings are removed and transported in boxes. This works for us, but when going to a show, it is all or nothing
Here's a Kato item that might be considered: