Julian
Modeling Pre-WP merger UP (1974-81)
The club I was involved with that had N-Trak modules used Atlas rerailer sections with a tie or two removed from each end so the joiner can be slid in place between the modules.
I'm sure the same thing can be done in HO, S, O or G (well, in G you can use rail clamps)
Kato makes an expanding track section for their Unitrack line:
http://www.walthers.com/exec/productinfo/381-20050
http://www.ntrak.org/documents/Manual.pdf
An old thread on the subject:
http://cs.trains.com/mrr/f/11/t/180852.aspx
Have Fun! Ed
You don´t state which track and which scale we are talking about.
On my N scale mini-modular layout, I used Kato Unitrack and made the connection between modules with nothing else than the bespoke Unitrack rail joiners - more information you´ll find here.
There are several other methods, like soldering the rails to brass flathead screws or ties made of copper-clad printed circuit board.
HO Scale, Atlas code 100 flex track.
I work in Free-mo (HO). The standard is that the rails stop an inch short, on each module. When two modules are joined, two inch long "fitter rails" are dropped in, with rail joiners slid back. Then the joiners, of course, are slid over and "centered".
Another way to do the connection is to have the rails go right up to the edge of each module, and do a SUPERB job of installation. Then they just work. I did this on my home layout that has several liftouts. Which, I suppose, you can argue aren't really modules. You can only really pull this off if only ONE person builds the whole thing--it suddenly becomes glaringly obvious what the problem was and WHO did it and WHO will have to fix it.
A variant of the above is to do the same thing but have a rail joiner slid back on one rail. You then join the modules. You then slide the rail joiner across the gap. I've seen it done, and it works very nicely.
The first (Free-mo) version has two advantages: The end of the rails are set back an inch. That protects them when you are juggling the module at a show or at home or in between. And there is also a bit of wiggle-room that the fitter rail can take advantage of.
The second version has an advantage: it's very quick to install and re-install (assuming you have guide pins, or the like). And there's no fitter rails to fiddle with. And fiddling with fitter rails is a negative with the Free-mo version--not a big deal, but still time consuming.
The third version is, in a way, better than the second: you don't have to be quite as picky about getting everything exactly perfectly ridiculously RIGHT. The rail joiner can "insist" on alignment. A little bit. Not as much as 2" fitter rails, though. Another advantage is, again, you don't have to fiddle with fitter rails.
The first version is best for when you have multiple people repeatedly joining up and disassembling modules. For a show.
The third works when there are the same pieces of a "super-module" that are ALWAYS assembled in a standard order--fer example--you have a 20' long module--that ain't fittin' in a van all in one piece. But it's still ONE module. By the rules, anyway. But, don't forget, the rails will go to the end and be very available for, uh, bending. In this case, people often have an end protector applied for transport and setup.
And the second version has its uses: when you are all by yourself and can control all the variables and know who to yell at when things go wrong. Definitely not one that works when multiple people are putting things together in multiple ways.
You can learn more about Free-mo standards by poking around this site:
http://free-mo.org/
Ed
First off, there are two types of modules, one is ment to be disconected and the other can be if a move occures. For the second one you just lay your track, perferably paralel to the front and just run as ussual, you will cut it if even needed. For the second there are a few ways that are done all the time, depending on scale and other things like group reqirements. One ho group I know of had expandable track sections (don't know if that stuff is still avalible in anything but G scale now), another used just straight track with regular rail joiners and put loose ballast in for the shows, vaulcumed it up and reused. So what are your needs?
Any that I recall seeing at shows use either a 3" or 6" piece of sectional track. The problem with having the track come right to the edge, using only joiners, is that the track ends catch easily on other things when the modules are being moved. Using a "spacer" piece of track puts the track end back from the edge, making it more difficult to snag on other things.
Good luck,
Richard
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."