Since the Bend Track standard design calls for a height of 50" and most of the traditional modules are a standard height of 40", there needs to be a way to match the two systems when they are being interconnected. We've toyed with numerous options, most proved to be too outrageous or costly. What we finally came up with seems to be the easiest, cheapest, and most practical solution. Actually, this method could be used anytime the height of two module systems are not equal and you want to use them together, not just for raising N-Trak 40" modules to Bend Track's 50".
Since there is a 10" difference in the height, we have taken a 2 x 2 and cut it to 1 1/4" x 1 1/4" x 10", drilled a 4" deep hole in one end and inserted a "T" nut so the existing carriage bolt from the shorter leg can be inserted for leveling. Then cut two pieces of 3/4" lumber, one at 2" wide x 16" long, the other at 1 1/4" wide x 16" long. Glue and screw these two pieces to two adjoining edges of the 2 x 2 x 10, careful not to drive a screw so that it enters the hole where it will interfere with the carriage bolt. Repeat this process until you have enough stilts for every leg. Now you have the option of clamping or bolting the stilts to your legs. For temporary uses, clamping would work just fine but if you plan on using them more than a few times I'd suggest going to the extra trouble of buying a few bolts, washers, and wing nuts and bolt them to your legs if you don't mind having two extra cross-holes in your legs. The nuts and bolts would be cheaper than buying four or more "C" clamps. If and when the need arises to lower your modules, just remove the stilts, unthread the carriage bolts from the stilts, and reinsert the bolts into your original legs and you're ready for your next setup.
The total cost is somewhere around $5.00 (per four-legged module) for the hardware to bolt the stilts on with, which is a lot cheaper and easier than building all new legs for each module that you want to raise.