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. Donīt 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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Đ 1996 - 2006 Lars Lundgen