Auto Couplers

Up to 1924 the VR used various types of screw (hook) couplings. The standard hook gear was attached to the underframe at each end of a vehicle. New gear from the 1880s was known as 'continuous' drawgear because the hooks at each end of the vehicle were joined by a solid bar or rod. This bar was supported by the underframe and the draw pull forces cushioned by springs at each end of the vehicle behind the headstock. Buffing forces were absorbed by the side buffers and the forces damped and transmitted down the sides of the vehicles through the side channel. As an aside, inspection of early Hobsons Bay photographs shows shackles at one end and chain links at the other. This is consistent with a north south rail operation where vehicles do not "turn" in service such as around loops and triangles.

During the early 1920s the railways experimented with several vehicles converted to auto coupler operation. New bogie auto coupled rolling stock was being introduced from 1925 and there appeared to be impetus to convert. The conversion would mean larger trains and a higher load to tare ratio equating to better efficiency. Certainly one factor was the safety of employees who would not be required to walk between wagons for coupling and uncoupling purposes.

All vehicles built new from 1924 featured auto coupler pockets and buffers with a transition hook for draw gear. This transition hook could then be replaced by an auto coupler shank at a later date. The new bogie stock such as J and E featured auto couplers with chain link transition gear. V vans were fitted with transition hooks. From 1928 conversions of freight stock to auto couplers commenced. This project lasted until roughly 1938. By this time all the stock that was required to be converted was done.

There were many problems with the introduction of auto couplers. Much like the early 1880s where many drawgear hooks, bars and links were broken on trains daily, so too did the auto coupler suffer. Verbose is the correspondence between VR and Bradford Kendall on warranty claims for poor workmanship and failed castings, with photographs to show the problems.

By the mid 1940's were several groups of freight rolling stock in service:

The auto coupler conversions saw some interesting changes. The main one was the change to underframes and the strengthening required for each frame to absorb buffing and tension forces. QR wagons recieved new centre sills which made the side tension bars redundant and were removed on the early series. UB conversions received transition hooks. The author belives the only reason these vehicles came into existence was the fact that new cast bogies fitted from 1933 cascaded older bogies onto QR wagons which then released diamond bogies. These spare bogies then allowed the VR to upgrade the 6 wheeler vans at minimum cost.

By 1952 VR were interested in removing buffers and hook vehicles at the first opportunity. This was the start of dieselisation and there are plenty of stories to indicate the problems of hook equipped wagons; by this time mainly the 10t/11t IB and IX wagons. One story has that diesel introduction lifted train speeds significantly and reduced the stopovers at stations, normally associated with VR operation: tender filling, oiling up, crew changes and shunting. This in turn caused a spate of hotboxes, with bearings than normally ran at low speed with frequent stops.

Photographs through 1952/53 show some auto equipped vehicles not fitted with buffers; stock that appeared to run interstate.

Z vans were fitted with the auto couplers and transition links were marked with a letter 'A' in the body corners as an indication. These conversion had been ongoing since 1934. The letter 'A' was to ensure the vans were not attached to passenger trains. Although sometimes they were attached due to necessity, in the main vans with the 'A' were restricted to goods train use. At this time the following van types in service were:

  1. Vans unsuitable for conversion and fitted with screw couplings
  2. Vans built from 1925 with steel underframes and auto coupler pockets and fitted with transition hooks ready for changeover to autocouplers
  3. Vans with modified underframes and fitted with auto couplers and transition links. These vehicles were lettered with the 'A'.

By 1954 all the screw coupled/hook fitted vehicles had been removed from service. So while it was true to say all hook equipped freight vehicles were out of service ( probably some 2-3,000 vehicles) the remainder of the fleet was still fitted with buffers and auto coupler heads fitted with transition links.

Between 1954 and 1960 during the nornal lift maintenance of vehicles auto couplers had the transition links cut off and the buffers removed as part of the overhaul. The vehicles were then retared. As there was an approximate reduction in tare of about 1 ton, vehicle loads were increased by the same amount: 15t to 16t, etc.

It would also be prudent to raise the point about Z vans and rough riding. This was a problem that only occurred when the buffers were removed. Specifically from the vans themselves but generally once the majority of stock had buffers removed. Screw coupled stock with buffers were relatively short trains. As stronger locos and auto coupling produced longer trains, the rough riding was not an issue until buffer removal. Until then the combined auto coupler springs and external buffers both provided damping. Once the buffers were removed the hard impact of slack run was felt: the shock being quickly trasmitted through the train rather than being absorbed by the springs in each buffer. Hence the trials in 1958 to improve rough riding and the ultimate remedy of long shank couplers.

As some older passenger stock was still fitted with screw coupled gear there was a need to retain some vans with dual coupling capability. It would seem that the normal freight use transition links were unsuitable for passenger working. This led to several Z vans being fitted with loco type couplings with the swivelling auto coupler head. With the rationalisation of codes in 1956, those vans ( about 19 ) fitted with loco type couplers were reclassed to "ZP" with the "P" letter now indicating a speed limit. These vans were used for transition between locos and non auto coupled carriage sets. By the late 1970s, these vans were surplus to high speed requirements and were reclassed to "ZD" where the "D" indicated "Dual coupling". These vans were used for movement of surplus suburban stock for scrap, transition vehicles for Way and Works stock and the occassional fan trip.

Peter J. Vincent

v4, June 2004