I wanted the shunting puzzle to operate hands free and also look as realistic as possible. The couplings on the railway wagons are fitted as standard with a coupling called ‘tension lock’, which is very reliable but doesn’t look very realistic. The best alternative I could find for the shunting puzzle is a coupling called Kadee.
The photograph below shows the tension lock coupling on the left and the Kaydee coupling on the right.
Fortunately, the Hornby Rudd and Clam wagons are fitted with a coupling socket called an ‘NEM’, which makes removal and replacement of the couplings really easy, all you have to do is push out the unwanted coupling from its socket (pinching together the fishtail shaped connections as shown in the photograph above) and push back in the new replacement.
The tension lock couplings are not compatible with Kadee couplings, so the wagon shown in the picture below, will not be able to couple to the shunting locomotive 09019 until the wagon coupling is converted.
Now that the wagon in the photograph below has been converted to Kadee type couplings, the locomotive 09019 and the wagon can now couple together.
The Kadee coupling system uses magnets for hands free operation. The picture below illustrates two wagons stationary over the magnet, which is positioned between the rails and the couplings on the wagons can be seen in the ‘uncouple’ position.
For the shunting puzzle to operate totally hands free, three magnets are used and they are positioned at the entrance to each siding. It is actually possible to operate an Inglenook style shunting puzzle with just one uncoupling magnet positioned in the head-shunt, but on this layout, due to the curve of the track, this was not possible and would cause the uncoupling procedure to be unreliable.