Edited version at 1753 hours:

The extended hidden sidings are now in use, but not before some re-thinking.

This blog started as a report on my building a super-lightweight layout - Wheegram sidings but has drifted from that purpose. However in an early edition of the blog, I described the cassette system developed for 'Wheegram'.

For Bowton's new hidden siding I decided to copy that idea but raise the adaptability level by having two types of cassette, - loco and train. That's what I have used on ' Birch Vale for many, many years, but those cassettes are based on aluminium angle and are of quite complex construction. So I thought I was choosing the best of both systems!

The basic idea uses copper laminate track with a wide sleeper termination. For the permanent, fixed track, a phosphor-bronze spring strip per rail is soldered to this and its adjacent normal sleeper. These strips are adjusted to push down but have an upward turned nose; they are also positioned to fit against the rail web. - see first picture

The cassettes also have a terminating wide sleeper and because they sit on thin, felt sliders, when clipped in place they push up against the phosphor-bronze strip. Mechanical fixing and electrical connection by the same device. - see second picture and third picture.

'Wheegram' had proved the idea but here, only train cassettes are used i.e. only one cassette at a time and always clipped by fixed springs. What I had omitted to think through was that the clipping of a train cassette to a loco cassette did not produce the firm downward pressure of the springs fixed to the baseboard! Who's a silly boy then?

I had decided that one end only of each train cassette needed springs and that a loco cassette could get by with no springs but relying only on the weight of train and cassette for the joint of 'train' to 'loco' gave too unreliable electrical contact. Back to the drawing board!

This was when I remembered that the complexity of the clip system on the aluminium cassettes was caused by this need for a pair of loose cassettes to produce opposing spring pressures.

Pictures four and five show my answer; - a strip of 0.018" brass araldited to the cassette base, below its spring clips. I've had a couple of running sessions and all is now working well. You can just see the edge of one of the felt sliders on one of these pics.

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This "warmer weather" season had been scheduled for scenic work on 'Wheegram Sidings' but as I write this, that "warmer weather" seems to have gone!

Dave