David, according to Guinness, 3rd Edition, 1979, JNR completed the change to automatic couplers in 24 hours, on July 17, 1925, after 8 years of planning.
Hirota also mentions the feat, noting that it involved 4000 locomotives, 10 000 passenger cars and 60 000 freight cars.
At that time, JNR used air brakes for freight cars, but vacuum brakes for passenger cars. Passenger locomotives of the period were dual-fitted. For example, the EE-built EF50 class 1.5. kV DC electric locos of the mid-1920s had both a 14EL air brake system and a vacuum brake system, as far as I know with a separate train brake valve and with a proportional valve to operate the locomotive straight air brakes. I don’t know when the JNR passenger stock was converted to air braking.
JNR seems to have adopted the 14EL schedule as a standard for locomotive brakes fairly early on, and new locomotives were equipped with it (or derivatives) at least until the mid-1960s. As 14EL was really outmoded by the early 1950s, I imagine that various updates and new features were added to suit JNR requirements without any change of basic designation.
Roger, the Australian and New Zealand Cape gauge roads presented an interesting mix of coupler and brake combinations.
New Zealand (NZR) basically used ABC couplers and air brakes, with automatic couplers used on some passenger stock since the 1930s I think, and more recently on some freight stock. I must admit that I don’t know what the current situation is. NZR was the first railway outside of North America to adopt the schedule 26L locomotive air braking system, in 1961. There was an interesting evolutionary pathway in that NZR had adopted the Australian A6ET/A7EL schedule as standard for main line locomotives around 1938. However, its very much off-the-peg GM G12 fleet of 1955 had 6SL, presumably simply because these were the standard fitment. 26L would have been an option for the 1961 G12 order, and evidently NZR saw the benefits despite the higher cost.
I’m not sure when Queensland Railways (QR) started the change from buffers to automatic couplers, but I think it may have been in the mid-to-late1960s. An operating manual I have covering the 1270, 1300 and 1620 class diesel locomotives shows the 1270 (introduced 1964) with buffers only, but the other two classes (introduced in 1967) with buffers and automatic couplers. QR was an early user of the air brake. I suspect that the combination of buffers and air brakes may have been unusual in the CMT gauge world, at least post the JNR coupler conversion. Australian railways generally were late adopters of the 26L locomotive air brake system. Perhaps because Westinghouse Australasia had a near-monopoly of the market, the A7EL and B7EL systems were used until the late 1960s. The QR 1320 and 2100 classes were I think its first fitted with the 26L system.
Western Australia (WAGR) used ABC couplers and vacuum brakes on its Cape gauge system. Air brakes and automatic couplers had been introduced at least by 1968, when the R class locomotives were introduced. These were dual-braked, using the reputedly very excellent Davies & Metcalf system. Presumably transition head couplers were used to facilitate interworking between automatic and ABC coupler equipped stock.
One source also reports that WAGR operated mixed braking system trains by interposing a brake converter wagon between the vacuum and air braked portions. The converter wagon incorporated diesel engine-driven air compressor and vacuum exhauster, and could convert either way with full retention of safety/emergency features. Although the core of such a unit would use familiar proportional valves, some complexity would be involved to prevent bootstrapping. One imagines that it would be necessary to use the pneumatic equivalent of a telephone hybrid. (British Rail and South African Railways also used brake conversion equipment. At least Southern Pacific in the USA and, I think, Commonwealth Railways in Australia used “repeater air cars” (SP terminology) with diesel engine driven air compressors to boost rear-end air brake performance in long trains.
Tasmania (TGR) used the very British combination of buffers and vacuum brakes. Automatic couplers were introduced at least by 1972, as the Z class locomotives were fitted with these as well as buffers. Air braking was not used until the 1980s, when the railway was part of ANR.
Commonwealth Railways Cape gauge basically used ABC couplers and air brakes, although I think that the Northern Australian Railway at one time had vacuum braked stock. At least one source reported that some of the NSU class diesel locomotives were fitted with vacuum brakes (in addition to A7EL air) for NAR operations. By 1965, it must have changed, though, as the NT class locomotives had automatic couplers and air train brakes.
South Australian railways Cape gauge and Silverton Tramway were both air braked, but I’m not sure about their respective coupler histories. Emu Bay Railway was vacuum braked and used buffers, although with automatic couplers coming in sometime after dieselization.
Evidently not much used “down under” was the bell coupler, which was I think quite common in Africa at one time.