Sprat & Winkle Mk.3 (AC7/3)
Description: An etched brass counter balanced hook suspended from the underside of a vehicle. A corresponding wire loop is required to engage the hook.
Method of operation: The hook engages with the wire loop on the opposite vehicle. It is in tension when pulling stock. When pushing stock a return hook engages the wire loop. To uncouple a chain with a magnetic link is pulled downwards. The return hook can be used to hold off the coupling to allow stock to be pushed to another location before separating. Uncoupling device: Strategically sited permanent or electro-magnets.
Modifications to stock: Wagons and coaching stock require a cutout in lower part of the buffer beam. This can be achieved by opening up the preexisting normal hook slot. Some modification to the underside of a vehicle may be required to provide a base for fitting the hook suspension.
Fitting common to all stock?: Only wagon and coaching stock need to be fitted with a hook. Locomotives only require the wire loop.
Compatibility with scale couplings: This system is not compatible with scale couplings.
Minimum recommended operating radius: 4 feet. It can be used around tighter radii but operation is compromised.
Instructions: A full set of instructions for typical installation and gauging is supplied with the fret.
Other Comments: It is known that the 4mm version is also in use on some 7mm models. A starter pack (S/AC7/3) containing all necessary components including permanent magnets is available.
Compiled by Bob Alderman.