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The TB-coupler


The TB-coupler



In my model railroad club, Skövde Modellsällskap , we have spent several sleepless nights discussing what coupler to use as a standard coupler. I made some very thorough tests of all the available couplers on the market at the time (well almost all).

The tests resulted in that the best ever made coupler was the Piko I-coupler but Piko stopped selling them in the early seventy s. Why, I can´t understand. That coupler had it all. It looked reasonably prototypical, had a smooth operation (you could couple two cars without ever moving the coupled car), it had delayed uncoupling in BOTH pushing and pulling direction, e.g you could uncouple the car and then either pull or push it to another place on the layout, and then with a small hitch in the movement of the loco, make the uncoupling happen.

Of course we looked at the Kadee couplers, They work great but are so very ugly. Have you ever seen an uglier piece of anything between your buffers. Why on earth should we Europeans cope with such a monstrous work of art. The thing is 2 or 3 times as big as a model of a human being. We are spending our time counting the rivets on the newest Roco loco, but we could without crying mount this big ugly coupler in the nose of Roco`s latest super model.

In 1980 a guy named Kent Hedquist wrote an article in a Swedish Hobby Magazine about a coupler that had been in use in O-scale since forever. He had tried it out in HO-scale and it worked well. Nothing ever happened at that time. No response to the article, but two years later, I started to play around with the couplers at home, and 1983 I converted my club to the coupler. My club, Skövde Modellsällskap, is the leading club in Sweden and the coupler met great interest at our annual open house 1983. The coupler is now a standard coupler among the clubs in Sweden and among almost all modelers who are building from scratch, building kits and buying brass locos and cars. There have been a few revisions of my old standard drawings and delayed uncoupling in pushing direction has been added.

The coupler is made from 0,2-0,3mm music wire and is of the loop/hook type. It is hardly seen between the buffers and you can add a prototype dummy coupler on the buffer beam as well. You can of course add the brake-hoses and other stuff that should be on the beam. You can uncouple them with magnets under the track or by hand, by putting a “magnet on a stick” in between the cars without touching anything. No modification of the buffer beam is done. There are two versions of the coupler, one with the hook moving upwards when uncoupling for freight-cars and one with the hook moving downwards for passenger-cars with diaphragms or bridges between them. We are using normal close couplers on passenger trains that are not normally split, but this couplers are fitted at each end of these “units”. The locos are fitted with only the loop part of the coupler (no hook), just to make the sight of the loco more prototypical. It is also possible to lower the loop on a shunter-loco, controlling it with one of the aux-lines of a DCC decoder. In that way you can do some nice shunting.

There is no cost in this coupler. No dealer get rich with this one. You buy it in a hardware-store by the meter or in rolls for almost no cost compared to e.g. Kadee or something you put in a NEM-pocket.

If you are looking at a train coupled with these couplers from the angle you love the most, I mean with one of your ears leaning on the layout and your eyes in buffer level, you can not, and I mean NOT, see the couplers, they are hidden behind the buffers. The cars are coupled 3,5 – 5,5 mm apart depending on how you are building the hook. If you are looking at the train from a “normal” angle you can almost not see it from a 1-meter distance.

We have pushed 40 car trains in a fairly high speed through the most difficult turnout-combinations with no problems, and I don´t know if 40 is the limit. We have not tested it though.




The TB-Coupler

Yes that is the name of the coupler in Sweden. The TB-coupler. It stand for the simple words for Wire and Loop in the Swedish language (Tradbygelkoppel or TB-Koppel). Well let us still call it the TB-coupler.

The coupler consists of 3 parts (four if you use delayed uncoupling)

a) The Loop (0,2 – 0,3 mm music wire)
b) The Hook (0,2 – 0,3 mm music wire)
c) The Hinge (a piece of a brass tube, a piece of a brass beam or a piece of plastic or the old NEM pocket!! or something )
d) The Delay mechanism (This one is an option)

Fig 1 is a normal freight car coupler, left picture with the hook down and right picture with the hook lifted.
Fig 2 is the inverted coupler for passenger-cars with bridges or diagrams
Fig 3 is the coupler from above, left the normal and right the inverted.

The inverted coupler has a counter-weight towards the middle of the car to hold the hook in the coupled position. The counter-weight part of the wire is cut from the picture, and not shown on the fig:s.

The couplers are uncoupled with a pair of magnets under the track, 32mm apart, preferably electro-magnets. The inverted coupler only uses one of the magnets as the uncoupler-parts are so close to each other. The couplers can also be uncoupled by hand with a “magnet-on-a-stick” device put in between the cars from above at a normal- and from beneath at an inverted coupler, without touching anything. You have to use other tricks when to uncouple one normal and one inverted.

The Loop

The loop is formed from 0,2 – 0,3 mm music-wire depending of how heavy trains you are going to pull. I am using 0,3mm. Drill two holes near the buffers (0,3 – 0,5mm) in the beam. Form the loop to fit in between the buffers not touching them, and put the legs of the loop through the small holes in the beam, and fold the legs and glue or solder the loop to the back of the beam. If you glue, use super glue, ZAP or any type of cyano glue, and reinforce it with baking soda. It hardens instantly when you pour baking soda in the wet glue. Do not be tempted to fix the loop in the buffers. The vertical flexing of the loop is of importance. Only if you have a loco (collectors item) that you refuse to drill the holes in, you can use the buffers to fix the loop to, only to be able to pull anything with it.

The Hinge

Drill the hinge. To big hole gives the hook to big horizontal play. The same with to short hinge. Glue or solder the hinge in place under the car. Use ZAP and baking soda if you are gluing.

The Hook

The hook is made of 0,2 – 0,3 mm music-wire. Cut a 120-140 mm piece of the wire and bend it 90 degrees in the middle and thread it through the hole in the hinge. Now put the hook-part of the wire in between the loop and the beam. Now you can start to bend the hook in shape from the hinge and out to the tip and out to the uncoupler part under the car. When cutting the wire at the tip of the hook, position the cutter in 90 degree to the “track” (parallel with the buffer-beam). In that case there will be no burr on the tip to inter fear with the loop when coupling with another car. Otherwise you have to round the tip with a sharpening-stone). Use a pair of tweezers (a pair of pliers are to clumsy) when forming the hook.

The Delay-wire (optional)

The delay wire is made from 0,1 – 0,2 mm non-magnetic wire (e.g. phosfor-bronze, is that an English word? I mean the same sort of wire you are using to wipe the wheels for power-pickup) soldered to the hook.


NO, NO PAINT! You can blacken them, but NO paint. Use weapon blackener, Blacken It, or some other chemical blackener, or leave them as they are. Paint will make the surface rough and coupling will not happen smother than other couplers. (TB-coupler couples smother than Kadee if not painted).

A small hint: If you bend some wire a little out of shape, just cut the part from the car and start over again. Don´t struggle with trying to re-shape anything. It will never be OK anyway, just cut it off and start over.

Good luck /Lars .



Drawings of the coupling.
Photos of the coupling.
Description on how to build the coupling.

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