Photos of Couplings
The photos in the Gallery of Couplings are the best that have been found from the Festiwiki site, but they could be better.
- avoid/redo pictures with the couplings in the dark shadow.
- avoid background clutter, such as wagons on another siding to the rear
- zoom into coupling to a greater or lesser extent to show.
- coupling with rolling stock number.
- coupling with little else.
- have a white/black measuring stick, in say decimetres and or inches.
- have parts of coupling painted in different colors to add to clarity.
- repaint rolling stock number where number is feint.
- in the case of the rail carrying wagons, show long bar between wagons in total.
- list other information such as
- height above rail
- drawgear capacity
- etc. FarleyBrook (talk) 04:19, 29 July 2015 (UTC)
Origin of FR chopper coupling
The current FR chopper coupler resembles that introduced in Norway by Carl Pihl about the same time that FR was changing over to locomotive haulage.
The first two narrow gauge lines in 1862 and 1864 had a kind of link and pin coupling, while the chopper coupling appears to have been introduced in the third line about 1866.
Who and when was the FR chopper coupler introduced, and did FR influence Norway or vice versa, if at all?
It is noted that some narrow gauge railways of this era, such as Tallyn and Queensland use scaled down buffers and couplers like normal gauge railways in UK. These couplers may have a highish minimum radius. It is probably true to say that a centre chopper buffer/coupler is probably needed to handle really sharp 2 chain curves.
Queensland had 5 chain curves on its original main line, as did Tasmania.
But South Australia and Western Australia used chopper couplings, with unknown minimum radius curves.
For more info on Norwegian NG. 
The old company originally fitted centre-buffers with hooks to the locos and the carriage stock all had the chopper couplings. A subset of the bug boxes were then fitted with the different couplings at each end (which is why they are seen marshalled at the top of the train). The guards vans (see historical pictures of Van 1) the had the opposite "polarity" so empty slate stock could be coupled on the way up, and the loco on the way down.
There are, of course, exceptions to this, where at least Prince and Palmerston were fitted with chopper couplings for use on the WHR and VofR. Look closely at the photo of Prince in 1964, and you'll see the chopper coupling is bolted in place of the centre buffer, rather than being on an arm.