Tuesday, 27 January 2009

Cassettes

As mentioned last month I have also being working on the cassettes for the fiddle yard. I already had some from Pen-Y-Bryn Quarry but I need more, particularly for the longer trains on Awngate. I also had some of the trunking left over. This had originally come from Focus DIY, sold as trunking to hide central heating pipes it is plastic, about 1.5mm thick and around 50 x 25mm U section. This gives ample clearance for 009 trains, and would probably be suitable for smaller 7mm scale stock too, certainly 14mm gauge industrial stuff.

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.

Next cut some PCB sheet to pieces about 5cm by 1cm, these should fit inside the ends of each cassette as shown and may need trimming to sit flat. These are glued in place with Bostik.

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.

Finally the rails are soldered to the PCB strips at the end of the cassettes, and the copper-clad surface of the PCB is cut through between the rails to prevent short-circuit.

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.



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3 comments:

Mike Beard said...

I'm still enjoying it. So much fun in such a small space. It makes yo wonder if Michael will build the "other end" on the other side of the fireplace!

Michael Campbell said...

Thanks Mike, but don't tempt me!

choo-choo-fish said...

Or even a link across the top of the fireplace!