I started portable modular layout building back in 1976 with the 18x36" Hickory Valley Railroad. It was later featured in MR in 1987 or so. Next designed module about five years ago was the logging branch, which was 21x42 and butts up to it, but is incredibly unwieldy in comparison, still working on that. But the PRR interchange scene always eluded me, I always thought it would be Ntrak until I researched that the minimal module size was 2x4, and with a 3-track main and restrictions on curves, it just wouldn't work to recreate the scene. So the interchange module of "West Hickory" was built T-trak as a standard triple and everything worked and fit. Then the connecting river bridge between the Hickory Valley mill and West Hickory, although single track, was built to T-trak dimensions - length and height. That started a quandary on how to ever use it with T-trak standard. That resulted in putting the second main track behind the bridge on a second single-track module, called "Thompson". Then to adapt the single-track modules back to 2-track standards took two new double modules on either end of the single-track triples - left side "Jamison" and right-side "Trunkeyville". Trunkeyville was also designed to fit West Hickory to close off the PRR interchange track, and Jamison will be designed to fit the other side of West Hickory to either represent local oil drilling or a local sawmill that had a 3' logging railroad of it's own with a Class A Climax - Nn3 maybe, we'll see. So it's a real collection of options, and the historic 1920's PRR line I'm modeling has a wealth of other locations that lend itself to accurately do in T-trak. Built into my home layout, well not quite. But yes. Now I've ended up with an entire portable modular layout concept with seven different modules, two free-lance and five T-Trak compatible. I've had all seven at Altoona the last two years, with the two logging railroad modules at my booth and the other five in the pickup T-trak layout organized by Dave Ferrari. This has been great fun, totally different from my big home layout, which is 1972 Santa Fe. It's semi-portable in that the tables can be disassembled without destruction, but it's only been moved when I moved. The modules are truly portable. And at least in Altoona, everybody and their brother shows up with PRR equipment to run over the T-trak modules, I don't even have to buy it to enjoy it running. There's four things I do that appear to be somewhat major departures in the T-trak world, completely unintentional though, matching more to my home layout standards: 1) tapering down the front edge of all modules like a riverbank, which greatly helps photography and realism. Girder strength is done by moving the front rib centered under the two main tracks. 2) Permanently mounting the skyboard, usually with photo backdrops, and lowering it to 10" so that storage and transport requirements are lessened. I transport by developing an end-panel so that two modules can be carried with one on top (upside down) in reversed orientation. Easy to carry. 3) Developing a way to do one-track T-trak modules with adapters, not unique, but combined with 1 and 2, possibly so. 4) Open season on track types once I get clear of the ends, with Peco regular and C55, Atlas C80, and Kato all mixing it up, but everything painted and ballasted (which is a heck of lot easier than ballasting Kato components). When Dave F. first saw my oddball modules he wasn't sure what I'd done, but after three years in the layout builds, he's OK with it.