Up to the mid 1880's the only brakes on the train were supplied by
Overseas this was the usual practice as well with various inventions including a long chain between the carriages being used to apply all brakes. All these independent systems failed when the train broke in two or partially derailled leaving the portion on the running still free wheeling or against the limited retardation of the hopefully applied van brakes.
Trains of this era would generally have been short. As braking was basically non existant, manipulating a train through the section would have been time consuming and reliant on good route knowledge. I also suspect, trains were halted at various locations before descending long grades to apply any vehicle brakes if fitted.
During the 1870s, two continuous brake systems were being developed
The vacuum system gained favour in England and was introduced into a hostile environment where each rail company thought they could invent a better mousetrap. Cost being the prime factor, few rail companies adopted continuous brakes voluntarily. The vacuum system has less brake force than Westinghouse and requires a larger brake cyclinder. Western Australia adopted the vacuum brake system.
The Westinghouse gained favour in North America as it was shown that better control of trains was possible.
The first Westinghouse brake systems were very crude; simple valves on the engine and vehicles. George Westinghouse himself drove trains when companies and drivers ('engineers') had braking problems leading to severe train shocks.
The Westinghouse system relies on air pressure differences in the train line to manipulate the brakes on the train. The system has three basic states
For VR, the brake pipe air pressures were 70psi for country trains, with suburban electric trains running at 77psi. In North America 90psi was the norm.
Whilst there are many questions that can be asked from the simple description above, it was a very simple overview that ignore many locomotive and brake valve features and enhancements since the 1920s.
There are three basic flaws in the Westinghouse system that have plagued railways for many years. These are
From the 1860's the VR was interested in a continuous brake system. But apart from crackpot ideas little was done. By 1884 the VR were testing three systems with locomotives and carriage sets fitted up for
The 'Woods Hydraulic' brake was developed by a Victorian engineer and was available for testing in 1876. Major problem with this brake was that in cold weather the pipes tended to freeze rendering the brake useless. In 1884 all three systems were tested at Werribee with more testing several days later at Gisborne on the 1 in 50 grades. With inconclusive results, trains of different braking types were relegated to different lines. By the end of 1884 large quantities of Westinghouse equipment was being ordered. Large scale conversions to WHB (Westinghouse Brake) did not appear to grow until the adoption of cast iron brake blocks from 1887.
All other stock was converted to the Westinghouse system. New construction saw the 'Quick Acting Triple Valve' being applied to all freight stock from the 1890s. This type of triple valve remained in service until superceded by the 'Improved Triple Valve' from the 1920s. VR stuck with the improved type until phased out in the 1980s. By this time train length and diaghram valves finally caught up with the 'rolling museum', years after modifications and brake developments had been progressing in North America.
The introduction of electric traction saw an EP brake experiment fitted to a Tait set. The 'Electro Pneumatic' brake consists of a brake handle with electric contacts/control and electo-pneumatic valves to the brake cylinders. Handle movement allowed simultaneous application, modification and release throughtout the train. Whilst this prevents propogation shocks through the train ( minimal on suburban sets ) the main feature of it is to allow an unlimited number of applications. With the air supply for braking directly piped from the main reservoir, there is no time lag to allow for the recharging cycle of the brake reservoir. The tests were not advanced and the equipment was removed. No doubt cost was a major factor and that an adequate system of brake existed.
In 1945 another brake test was conducted. This was 'Tyers' brake a modified pre-release system that allowed lower brake cyclinder pressure when the train came to a stop. This was to prevent the jerking of the carriages with high brake cyclinder pressures. Tyer was employed by the VR and was trying to the EP type gear that NSW were using in Sydney without the expense of purchase. After several static trials at Newport Workshops, the tests were abandonned.
At this time in the USA, Southern Pacific were running country steam hauled passenger trains with EP brake.
EP braking was introduced to Victoria by a test Tait set in 1924. With testing finished shortly after, the next trains to be fitted with E.P. braking were the Harris trains of 1956. Rheostatic braking was trialled on a Harris set in the late 1950s but was removed at a later date. Rheostatic braking is where the traction motors become generators and the power created sent to cooling grids. The Harris rheo brake was limited to a standard retardation and could not be controlled from the drivers brake. Any increase or descrease in braking was limited to the tread brakes on the trailer cars, or by releasing the brake entirely.
The Hitachi/Martin & King trains of 1972 featured Westcode EP braking with an overlaid rheostatic brake. Westcode braking is discrete system of seven steps of braking between minimum and maximum brake with the brake controller sending an electric code to the brake unit. To reduce cost of the trains, the rheostatic braking was 'naturally excited'. This meant the field around the traction motor to start the current generation was not provided by an external source but was naturally induced at the time of the brake call. This caused the trains to be rough at start of braking and tended to grab at speeds lower than 65km/hr due to excess current being produced until such time as the switch gear could be regulated.
The Comeng trains in 1981 were fitted with Westcode brake and featured an excited rheostatic brake which was very smooth and could be controlled at all speeds in the electric brake range.
This page is presented as a broad overview of the 'brake' scene on the VR. This is by no means definitive and those wishing to learn more are urged to conduct more research. There is a good site at http://www.railway-technical.com/ for a more detailed overview.
Basic data from
Peter J. Vincent, revised to April 2008