Terry
Our portable might offer some concepts and the price was less than Mike's.  Our construction was less given that we did not utilize a frame along with smaller sections of 3x4 vs. 4x8 straights on the main runs.  We used poster board/plywood 3/8" (plan to replace not that it is bad but too much flex) with 3/8" marine plywood.  We did bondo (auto body repair) but next time clear enamel paint will work to water proof.  It has been outdoor with a Memorial day(end of May) through November.  We disassemble it given most indoor shows occur from Nov through April therefore available such as York.
Here is an overview of the build.  http://archive.mylargescale.com/forum/topic.asp?TOPIC_ID=27111 
Original cost estimate was:
Rough estimate of project costs:
Platform supplies and parts: $1370
Track and switches: $1420

Well, with revisions of track and switches one could easily double that cost.  Platform supplies materials went up with the cost of yellow saw horses, so new estimate would be $4870 complete.  We are building a rolling cabinet to fit into the van so the track is better organized and safer during transport.

The entire 30x58 foot layout fits easily into our van with room for equipment:

Since that post we have change track to Accucraft and utilized larger switches plus add a freight yard.  Future plans are for turntable with engine storage, another straight section on each main run.  We will revisit our curve switches due to their construction and lack of adequate frogs, probably straight #8 instead.



The freight yard is in the background of the right side

I have gotten a few requests for information on the construction of the portable track so I will add a brief description here. Currently, the track is packed up in its trailer so pictures will have to wait until after the next setup. If I get time I will do a longer write-up, perhaps as a SitG article.

The frame of each section is a modified PETS frame made of 1" square aluminum tube. The PETS system has been discussed in earlier posts. The tops are Dibond, which is an aluminum/plastic composite that has the same expansion rate as aluminum. The Dibond is glued to the frame with Gorilla glue. This makes a strong and stiff combination. A previous version used 3/8" marine plywood which was heavier and prone to sag.

The legs are telescoping aluminum pipe. The upper/outer leg is 24" long, threaded at the top with a through hole at the bottom. The inner leg has through holes spaced 2" apart along the lower 18" of its length. Coarse adjustment is accomplished by inserting a hairpin spring clip through the outer leg hole and the appropriate inner leg hole. Fine adjustment is accomplished via a 1/4" bolt at the bottom of the inner leg. The legs are held to the frames by pipe flanges. The pipe flanges are bolted to 1/4" aluminum plate welded to the frame.


I would like to add that I think posting an email address without consent on an open forum is a not a good practice. myLargescale has a facility for reaching members via email without exposing their email addresses and I would hope that myLargescale members would use that facility.

Mike Moore