Couplings

This is a small device at the end of each item of rolling stock, which fades into insignificance in comparison with the precision and detailing of the latest coaches and wagons. Having said that, it is probably the most important part of the model - if it fails to operate correctly it will ruin your fun.

Let’s take a closer look at couplings.

Connect up seven Hornby Dublo coaches and pull them along the track. You will be amazed at the weight and the drag. Now pull them around a curve and notice how the resistance increases. So Hornby Dublo adopted Peco’s original Simplex coupling to bear this weight. Modern rolling stock has pinpoint axles and bearings and there is very little resistance, hence today’s light and somewhat flimsy couplings. Nevertheless, it is still important to keep the wheels clean and remove all dust and dirt deposits. This, along with regular maintenance to ensure free running, helps immensely to keep the drag to a minimum.

So imagine two coaches have become derailed - yes it even happens at Hornby Central. It is essential that they can be easily disconnected and placed back into the train with ease. Some couplings, mostly modern day ones, require twisting and turning, and even then only come apart with luck! Every twist is in danger of damaging the coupling as well as causing frustration.

Other coupling techniques require a tool to release them. Patience is the key here, as you have to be so precise and it is time-consuming. We are not very patient, especially when the train is running late or our tea is getting cold! Then there is the compatibility problem: not all manufacturers fix the same couplings so it is impossible to mix and match perfectly.

This brings us to the most important feature of all, the automatic release and connection process. We chose to use Peco’s original Simplex Coupling, later adopted by Hornby Dublo. The basic principle being two hooks interlocking, allows stock to be lifted off the tracks without any problem. You cannot get simpler than this. Add a downward prong towards the track and you have your release mechanism. In Hornby Dublo days you could buy an un-coupler rail. A lever lifts a platform which connects with the prong and releases the hooks. The problem is, you still had to operate it manually, which meant you had to go to the train. Later this mechanism was electrified; now you’re talking a click of a switch and the rolling stock releases. The problem is the appearance; it is ugly and unrealistic. In practice it works, so with a little innovation we have developed our own system.

Peco's permanent magnet in the track

At the uncoupling point along the track, we lay a Peco permanent magnet, designed for use with their Magni-Simplex auto-coupling unit. However, we do not use the auto-coupler but adapt the original Simplex coupling, by simply bending the downward prong inwards and then slightly outwards, sufficient only for the coupling to just clear the permanent magnet in the track. As the train passes over the magnet, it tries to split the two downward prongs, but can only do so when the tension is released. So when uncoupling is required, it is only necessary to reverse the train sufficiently to release the tension on the couplings. Obviously, to reconnect, the truck must not be over the magnet; simply push it off the magnet. We find this works perfectly. Please feel free to try it yourself.

This method can also be effective with the Hornby Dublo heavy duty plastic coupling. However you will need to drill a 1mm diameter hole through the plastic coupling, as per the picture illustration, and insert a 10mm long, 1mm diameter steel pin, adjacent to and behind the existing plastic drop down prong. This hides the pin, but the pin will react over the magnet just as the prong does with the Simplex coupler.

10mm steel pin inserted in Hornby Dublo plastic coupling.

This method does require accuracy and precision, especially if you are coupling the Peco and Hornby coupling together. The couplings must be exactly the same height on every item of rolling stock. The angle of the hook must be correct and the magnet must sit perfectly flat across the sleepers or it will make contact with passing trains.

Anyway, it works for us: a system which is as old as we are (!) and is also simple, reliable and aesthetically acceptable.

Upcoming Exhibitions

10
Mar

Keighley Model Railway Club

Saturday 10th and Sunday 11th March 2018. Venue: UAK Green Head Rd Keighley BD20 6EB

Please contact us for more details on our upcoming exhibitions, or, if you’re an exhibition manager and would be interested in our display, please get in touch.

Our Track Tricks

Laying the Track

Coaching Stock

Trucks and Wagons

Use of People

Landscaping

Explore Hornby Central

How we make the trains run

Remaking History

The Making of Princess Anne

The Making of the Layout

The Making of our Steam Specials