In July 1957, Mr. D.C. Robertson, a former railway engineer and Senior Lecturer in Civil Engineering at the University of Cape Town, and chairman of the Cape Town Branch of the S.A. Institution of Civil Engineers, wrote three articles dedicated to the history of railway sleepers for the magazine.
The first article, titled Railway Sleepers: Development and Technical Aspects in Southern Africa, sees Robertson reviewing the development of sleepers on early railways before discussing the first sleepers used by railways in Southern Africa.
He also describes the efforts before and after the Union in South Africa to grow timber for sleepers, the importation of wooden sleepers, and the switch during the inter-war years to steel products.
The first railways ran on granite setts grooved to receive the iron tyres of the wheels. This was before the days of steam locomotives. The “rails” were used in quarries and mines where loads were heavy. Thus, both rail and sleeper were incorporated into one in the earliest railways.
With the advent of steam traction in 1823, railways developed new characteristics. Distances became longer and speeds faster. In 1848, a train ran 53 miles (roughly 85km) in 47 minutes. This was the iron and steel age, and it was natural that iron and steel should form the track.
In England and the newly formed Kingdom of Belgium, with their good supplies of iron and coal, railways developed rapidly in the 1830s. The first sleepers used were not transverse; they were cast iron pads or “pots,” placed one under each rail and connected by an iron bar to maintain the gauge. However, such a track was not rigid and therefore unable to withstand the vibration and oscillations of high speeds without continual maintenance.
It was in North America that the use of timber transverse sleepers or “ties” first became universal. The great railway expansion there in the 1850s and 1860s called for millions of sleepers, which were available in the vast forests at the time.
Timber rapidly superseded the old “pot” sleepers in world railways. It became the ideal material because of:
- Its relative lightness and strength,
- Its capacity to absorb shock without failure, an ideal attribute for a railway track,
- Its capacity to be treated with preservatives to extend its life,
- Its salvage value.
South Africa
In South Africa, the first inter-town railway, from Cape Town to Wellington via Stellenbosch (about 72 miles or roughly 116km), was opened in 1863. This railway ran on pot sleepers and was built to European standards, with a gauge of 4’ 8 ½”. The development of the diamond fields in the 1870s saw lines being extended inland from the coast, from Cape Town, Port Elizabeth and Durban. These lines were developed largely on steel sleepers, commonly known as “lug sleepers.”
Construction Progress
The closing years of the 19th century saw vast railway construction progress in Southern Africa. Although the tropical regions were well supplied with forests suitable for sleeper production, the presence of white ants made it impossible to use timber sleepers on these early lines.
The success of the early steel sleepers was mixed. Westwood and Winby sleepers, laid in 1889 on the line from Komatipoort to the old Selati Goldfields, were still in use 41 years later. However, on the C.S.A.R., steel “lug” sleepers developed defects about 15 years after being laid. As traffic increased between the seaports and the rapidly developing hinterland, the steel in the rail seats began to fail due to metal fatigue.
At the time, steel stressed to its elastic limit failed after approximately 6 million repetitions of load. Considering 20 trains a day with each having 50 axles, there would be 365,000 repetitions of load per year. After 14 years, failure was inevitable, which was indeed the case.
Wooden Sleepers
Owing to the failure of the early steel sleepers on the main lines, South Africa switched to wood sleepers on a large scale between 1914 and 1924.
Australian Jarrah sleepers were found to be suitable for most localities, and large quantities were purchased annually from the Australian Government. In general, these Jarrah sleepers required no treatment against timber pests.
Special ships were purchased by the South African Government to transport sleepers from Australia, with some 250,000 sleepers imported annually.
Steel Sleepers
By 1927, the pendulum had swung back to steel sleepers. A new, heavier design was perfected in two types to suit 60 lb. and 80 lb. track. This step was necessary because, between 1924 and 1934, about 2,000 miles of new construction was completed in South Africa, requiring around 4 million sleepers.
Due to the special equipment needed, these sleepers could not be manufactured in South Africa, and millions were imported from Belgium and Germany. Between 1931 and 1938, 11.6 million steel sleepers were purchased overseas, with the largest (and last) shipment being 3.3 million sleepers in 1938. As war threatened, supplies ceased.
Local Supplies
The early colonial governments in South Africa were well aware of the future expansion of railways. Before 1910, they established sleeper plantations across what was then the Union of South Africa. Fifteen plantations were initiated, ten in the Cape Colony, three in the Transvaal, one in the Orange Free State, and one in Natal, covering a total of 66,409 acres.
Tratman stated that one acre of North American forest could produce 80 sleepers per year. Based on this figure, the acreage seemed sufficient, and the scheme demonstrated wise foresight.
Unfortunately, Southern Africa’s climate is not conducive to growing large timber trees. By 1933, the Railway Sleeper Plantations showed little promise, and as a result of the Granet Report (Sir Guy Granet toured South Africa in 1936 to report on railway matters for the South African Government), the plantations were transferred to the Department of Forestry.
There was one exception: the magnificent Knysna forests produced excellent timber trees. Between 1931 and 1936, some 622,000 sleepers (mostly Yellowwood) were harvested from these forests. Around the same time, large quantities of Rhodesian sleepers, about 300,000 per year, were brought into the Union.
In the immediate post-war years, sleepers were imported from the United States, West, Central and East Africa. Official reports reveal that importing wooden sleepers during this period was always challenging.
World Shortage
Every country faced a shortage of wooden sleepers. In Great Britain, just before the nationalisation of railways, Brady estimated that British railways were short of 10 million sleepers. Britain, France, Germany, Holland and South Africa all began experimenting with substitutes.
Britain started with a wartime reinforced concrete sleeper but soon switched to a pre-stressed concrete type.
France experimented with both plain and pre-stressed concrete.
In South Africa, hundreds of thousands of sleeper blocks were used on loops and sidings to ease demand.
It became clear at the time, that the world’s forest resources were insufficient to supply railway sleepers to meet modern progress. Cleared lands had not been replanted, and the remaining primeval forests either lacked transport or were being conserved by forward-thinking governments.
The supply of Burma Teak sleepers had ceased. Jarrah sleepers were in short supply. The United States had hardwood and softwood sleepers for export in controlled quantities.
The last reservoirs of sleeper supply were the Amazon Basin in Brazil, the forests of Central Africa and the softwood forests of Siberia. These areas were undeveloped and lacked transport. A mission to Brazil a few years earlier found abundant timber but little labour and less transport to develop the supply.
These areas will eventually be exploited as development progresses. At the time, it was hoped that cutting would be carried out on a planned basis, with forests replanted once stripped.
By 1957, most countries had learned their lesson, and forest conservation, as opposed to the wholesale cutting of the past, was widely practised.
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