The third possible origin may be that the line is simply named after a type of railway coupling.

The problems with common earths in railway couplings are similar to these phantoms.

Early railway couplings had been found to be prone to breakages.

See Railway coupling conversion.

Willison coupler, a railway coupling.

The SA3 coupler is a type of railway coupling used mainly, but not exclusively, in Russia and other states of the former Soviet Union.

At the sametime the railway coupling (which was a Buckeye coupling) was replace with same type fitted to the later class 142, for more flexible working.

In a similar fashion, railcars are usually equipped with hermaphroditic railway coupling mechanisms that allow either end of the vehicle to be connected to a train consist without having to turn the railcar around first.

Many items, before they came to be made of mild steel, were produced from wrought iron, including rivets, nails, wire, chains, rails, railway couplings, water and steam pipes, nuts, bolts, horseshoes, handrails, straps for timber roof trusses, and ornamental ironwork.

In an endeavour to reduce working expenses, it was decided to experiment with the use of steam tram motors and cars with railway contour wheels and a motor with trailer car, also dummy truck with dual tramway and railway couplings, were brought from Sydney for this purpose.