This trial pack contains a fret of 8 AC3/3 delayed action autocouplings and MP4 mounting plates for use on 4mm finescale layouts. This style of coupling is particularly popular with EM gauge modellers. They may also be used in 3mm scale, but some trimming of the mounting plates will be needed to make them fit.
Also included are lengths of BW brass wire, NSW4 nickel silver wire, SIW4 soft iron wire, and a 4MAG permanent magnet. The inclusion of the mounting plates enables the AC3/3 coupling to be used on curves down to 2′ radius, compared with the normal recommended minimum of 4′. They also have the added advantage of making the couplings easier to fit.
The frets shown are etched in 0.015″ brass. Each coupling is 24mm long and 8mm wide; the mounting plates are 22mm wide x 8mm deep. The magnet is 25mm long, 7½mm wide and 4mm deep.