The Alex Jackson Coupling
Page 1: Introduction and history
This coupling was developed by Alex Jackson in the early 1950’s, but it still proves difficult to be exploited commercially. However, by making the coupling yourself it is cheap and, provided you follow the design carefully, a reliable and surprisingly robust coupling.
Details of its construction appeared in the January 1960 Model Railway News, written by John Langan who used the coupling on his “Presson” layout. Those who saw it would marvel at the shunting that went on without the hand from the sky being involved in the process. It was used regularly by the Manchester EM group including Sid Stubbs, Norman Dale and Norman Whitnall. More details of its manufacture and use appeared in the Model Railway Journal numbers 55 & 56 and it is these articles that are probably more easily obtainable today.
Since the 1960’s there have been some significant developments in the operation of the coupling and modellers continue to use the idea to develop their own version of it. What is apparent is that the design that Alex developed all those years ago is still a great way of providing hands free coupling and uncoupling of stock.
Who was Alex Jackson?
The late 1940s and early 1950s was a period when many developments were taking place in the hobby following its revival after WWII. At that time, Alex Jackson gave much encouragement to many fellow modellers by his brilliant approach to the problems of mechanisms, good running, trackwork, and true scale modelling. He first worked in a scale of 3/8″ to 1 foot (1:32) and his garden railway, running off 100 volts AC supply, was a source of enjoyment to all who visited him. Stories exist of his unfortunate cat which never seemed to learn to keep off the track when a running session was in progress – with surprising results!
A fine example of one of his locomotives in 3/8in scale may be seen in the March 1948 Model Railway News. Later, Alex changed to 4mm scale EM gauge, 2 rail using split axles, metal wheels and insulated frames for locomotives. He saw the advantage of using the higher than usual voltage of 24V DC which was quite revolutionary at that time. This, of course, meant the need for home built motors which he used with flywheels to obtain smooth and controllable running which can still be compared with the best of today. No gimmicks in the controls either, just a plain resistance wire controller. His attitude to modelling and an example of his construction methods may be seen in the description of his 4mm scale LNWR 0-6-2 side tank locomotive in the MRN for June 1950. The photograph clearly shows the early version of his coupling. Alex died in October 1952 after an operation, when he was in his early thirties, and the hobby lost not only a most distinguished exponent but an enthusiastic leader who by his example helped to raise the standard of modelling to a level which we still appreciate today. The Alex Jackson or AJ coupling is a fine memorial to this pioneering modeller.
Alex first demonstrated the coupling at a meeting of the Manchester Model Railway Society in February 1949. The Society continues to receive enquiries for information about it and, although the coupling in its basic form has changed very little since its conception, a revised description which includes further information on the latest jigs to aid its construction is now presented. The Society believes that nothing can beat the visual appearance of screw and 3 link couplings but, if hands-free coupling and uncoupling are required, then the Alex Jackson Coupling is the most unobtrusive and versatile automatic coupling available. It has been in use in one form or another for over 60 years, but it must be emphasised that whilst it is capable of satisfactory operation in the hands of careful modellers it is not suitable for very rough handling, and accurate maintenance of all angles and dimensions is essential for faultless operation.
By accurate setting in the first instance and maintaining this setting from time to time, the coupling will operate faultlessly and indefinitely. Its main advantages are:
1 It is unobtrusive.
2 It is quiet in operation.
3 It is reliable if properly made.
4 It is cheap.
5 Couplings are identical at each end of the vehicle, so that turning end to end does not affect performance.
6 No mutilation of wagon headstocks or attachment to buffers is necessary.
7 The pull for uncoupling, being downwards, ensures that the vehicle stays on the track.
8 The electromagnet may be energised by a push button on the control panel before a wagon reaches it with the certainty that it will uncouple as the wagon passes through the magnetic field.
9 Uncoupling while moving, with the loco pushing and buffers under compression with couplings slack, is positive and the magnet will operate only one coupling at a time.
10 Only one uncoupler is required per fan of sidings.
11 After being uncoupled at the magnet location, vehicles may be parted and left at any position on the layout. This allows realistic shunting to take place.
(NB: Some of the advantages listed above are superseded by DCC operation of the coupling, which gives even greater flexibility of operation – this is discussed briefly later on.)
The ingenuity of the coupling lies in the design of the hook.
Modellers may be put off making and using the couplings, but the jigs produced by Palatine Models and described later do ensure that correctly made couplings are produced.
Each feature is important and plays a part in the action of coupling and uncoupling. The method used for forming the hook, as devised by Norman Whitnall, requires the wire to be bent back along the top of the nose with the tail coming down on the right side of the shank when the coupling is viewed end on. This ‘handing’ is important so that wagons will couple with each other. This way of bending the hook shape produces a strong hook which tightens upon itself when under load and is capable of handling long trains. The hook does not require to be soldered but this may aid longevity and reduce maintenance.
The material used to form the hook is 0.011inch diameter spring steel wire (32 SWG or 0.274mm).
This is easily available from a music shop in the form of guitar strings and the picture shows a common variety.