Historical information
During prestige, long distance train journeys some carriages had air-conditioning, and the majority of passengers had to brave unheated carriages. To offer some comfort during the winter months, the non-air-conditioned carriages were provided with footwarmers. These were metal containers roughly 100 mm thick and 300 mm wide, and about 750 mm long, which were filled with salt crystals (concentrated crystalline hydrated sodium acetate). The footwarmers were covered by sleeves of thick canvas, and two footwarmers were usually placed in each compartment of non-air-conditioned carriages.
To activate the chemicals, the footwarmers were heated almost to boiling point. This was done by removing the canvas sleeves and placing the footwarmers in a large bath of very hot water. After they had been heated, they were removed from the bath and the sleeves refitted. They were then ready to be placed in the carriages.
The McLaren patent foot warmer was used on railways in New South Wales, Queensland, Victoria and South Australia as well as South Africa and New Zealand. It was during the 1901 royal visit by the Duke and Duchess of Cornwall that these foot warmers were first used in New Zealand in the royal carriage.
Before railway carriage heating was introduced, McLaren patent foot warmers were placed on the floor of New South Wales government railway carriages from 1891 to provide a little passenger comfort. The rectangular steel container worked a bit like a hot water bottle but instead of water contained six and a half kilograms of loosely-packed salt crystals, (concentrated crystalline hydrated sodium acetate). This was permanently sealed inside the container with a soldered cap.
After the foot warmer was heated in vat of boiling water for about one and a quarter hours the crystals became a hot liquid. (The melting point for sodium acetate is 58 degrees). There was a whole infrastructure of special furnaces set up at stations for the daily heating of foot warmers. By 1914 the Victorian railways had 4,000 foot warmers in service and by 1935 there were 33 furnaces at principal stations to heat them.
After about 10 hours the container was picked up by the handle and given a good vertical shake which helped the cooled liquid reform into a solid mass of hot crystals. Staff or sometimes passengers shook them en route when the foot warmers began to get cold. However, as they were heavy this was only possible by fit and agile passengers. At the end of the journey the containers were boiled again for reuse on the next trip.
Sodium acetate railway foot warmers were introduced in Victoria in 1889, Adelaide to Melbourne express in 1899. "Shaking up" on this service took place at Murray Bridge and Stawell on the tip to Melbourne and at Ballarat and Serviceton on the trip to Adelaide. The use of foot warmers began to decline in New South Wales from the 1930s with the first trial of carriage air-conditioning in 1936, steam heating from 1948 ad LP gas heating from 1961. By the early 1960s the main services using foot warmers were the overnight mail trains.
info from : http://www.powerhousemuseum.com/collection/database/?irn=67564#ixzz4UBNzVf6t
Under Creative Commons License: Attribution Non-Commercial
There was a whole infrastructure set up at stations for the daily heating of foot warmers in special furnaces. In Victoria alone in 1935 there were 33 heating works.
Significance
Historic - Victorian Railways - Carriage Heater - Foot warmer
Physical description
A rectangular-shaped stainless steel casing with a welded seam down the back and welded ends. There is a handle at one end for carrying and shaking. Inside the foot warmer are two baffle plates and three trays to contain the sodium acetate. There was a cast-iron ball in each internal compartment.