The boards have the standard track spacing (67 mm) perpendicular to every join, so in theory pieces can be connected in different ways, and most importantly, a roundy-roundy layout could be produced quickly, then more sections added as they were built.

Joining the boards needs to take into account 3 factors:

1- Physical alignment of the rails - to prevent derailments

2 -holding the baords together (they are easily knocked by children dancing around

3 - electrical connectivity between the rails on each section

The segments are made of 6mm ply sat on 30*10mm softwood perpendicular to the tracks at the end. I went through a variety of ways joining them, but the system I ended up with (Mark I) was to use M6 bolts and furniture nuts (see photo). The holes are standard spacing (under the centreline of the track). I use a bolt turner, connected via an angle crank to a battery drill to quickly tighten them (see photo). I decided to keep the rail joiners to connect each section. This can be incredibly fiddley (as you not only need to get the horizontal alignment of the track right, but also the vertical alignment, and both tracks need to be joined at once. The rail joiners alone are not enough to hold the segments together, as they often got knocked apart by overexcited children dancing around, so the bolts are still necessary. You also need to be careful that when you separate the boards - the rail joiners protrude and are share and can easily cut little toes - ask me how I know! However, the rail joiners sovled the rail alignment problem and the electrical connectivity.

As you can see from the photo, you need to only put the furniture nut on one side, on the other side the bolt just passes through a 6mm hole. I had a convention that on the inner track the bolts protruded in an anticlockwise direction (the direction of travel of the train...)

The furniture nuts required and 8mm hole and were screwed in with an allan key.

30mm gives enough for the bolts to be attached under the track, and also clearance for a point motor or servo.

The boards simply sit on the laminate floor (or the lounge carpet when my wife is away :).