Well the pictures are there but probably need some explanation, so, from the top:

Picture 1

The green bit is the hinged extension designed to hold the two boards together when in the folded position. The machine screws fasten into pronged 'T' nuts fixed into the board end.

There is a step in levels shown here to. That's the start of the hidden sidings which are cassettes. More about those later.

Picture 2

The hinged extension folded down to running position and extending the length of the hidden siding.

Picture 3

Showing the Paste-board hinges and the means of clamping the two baseboards tightly together.

Picture 4

The whole lot folded for transport. I included the 12" steel rule to give an idea of sizes.

Picture 5

Showing the step in levels. The step depth is equal to the thickness of the trackbed on the cassettes.

When I add to this blog next time, I'll include shots of the track developing.