First job then is to cut to length. I marked with a square (which didn't turn out to be that square but never mind!) and cut with a junior hacksaw. A new blade is well worth having! Then clean up with a stanley-type knife and a big file, just to make sure the ends are reasonably square and tidy.
I made 2 train-length cassttes of 30cm (so I have 3 in total), 1 standard loco cassette of 9cm (4 in total), 1 longer loco casstte of 12cm, and a full-length cassette of 42cm to allow any train to be made up including loco. I also have 3 of shorter 21cm train cassettes, which will be fine for short passenger trains or railcars.
The track is then cut to length, here it is PECO 009 flexi-track. Using set-track wouldn't be a bad idea as it is dead straight! Note that the end sleeper(s) are cut away to clear the PCB.
To get the track central I had made up some 40-thou plasticard jigs when I made the original cassettes. These fit tight into the cassette and have notches to fit over the rails, such that the track is dead central in the trunking. The track is glued in place (again with Bostik) and aligned with these jigs, ensure that the track is straight and that the rails are flush with the end of the cassette.
As previously shown the fiddle yard entrance has a similar arrangement with brass wipers that make contact with the PCB, so a cassette is simply pushed in place and electrical contact is made. Where 2 cassettes are used together only the cassette joined to the lead track has power, which is fine as that is the loco cassette when leaving the fiddle yard, and when a train is run in it runs through the train cassette and stops when the loco runs onto the loco cassette at the end.
For alignment the cassettes are pushed against the back edge of the fiddle yard, or they can sit between strips of wood or plastic L-section.So that is not the most accurate cassette system, but it is one of the easiest to make, and works well.