SA’s Sheffel Bogie keeps on rolling
One of the overarching visions of the British businessman/ entrepreneur, Cecil John Rhodes, was to build a railway from Cape to Cairo. Because of the mountainous terrain, and the lower cost, Rhodes introduced an unusually narrow gauge railway track of 3.6 feet (1.065m) into the southern African region.
This choice was a good option for the relatively slow rail transport used at the time, and was even adopted in parts of Australia, New Zealand and Japan.
But the disadvantages of a narrow gauge track soon became apparent. It was not suitable for high speed trains, because the carriages were unstable when rounding turns; it also caused a great deal of vibration in the carriages and wear and tear on the metal train wheels and rails.
The problems of speed and stability threatened the viability of the railroads, and created a perfect situation for someone with “can do” spirit to come up with a solution to the problem.
The man who stepped up to the plate was a mechanical engineer, Dr Herbert Sheffel, who worked in the rolling stock design section of the South African Railways (SAR). He realised that, if he could redesign the suspension of the bogie, he could solve the problem.
A “bogie” (or “wheel truck” in the US, Canada and Mexico) is a chassis or framework carrying wheels that is attached to a vehicle, such as a railway carriage. Originally, railway wheels were rigidly attached to the framework of the coach, but independent bogies were first introduced on to British rail coaches from 1874.
Bogies usually have two axles and four wheels but multiple axle bogies have also been developed to carry very heavy loads.
The bogie serves several purposes: it supports the railway carriage, it stabilises travel on straight and curved tracks, it ensures a smooth ride by minimising vibration, it minimises centrifugal forces when the train runs on curves at high speed, and it minimising abrasion and wear on the metal wheels and tracks.
Many different kinds of bogies existed, primarily for wide gauge railways. In the 1970s Sheffel set about inventing a new, high-stability bogie for narrow gauge railways.
Instead of a rigid bogie with a rectangular chassis, he designed a flexible “cross anchor” bogie with a high wheel profile that allowed the inner and outer wheels to accommodate to each other on curves, and also dampened the lateral forces that produce vibrations.
The “Sheffel Bogie” was introduced to the SAR fleet of ore wagons from 1975, and proved to be a great success. It reduced wear and tear on the wheels and rail tracks, and provided a stable, vibration-free ride.
The bogie has saved South Africa millions of rands in railway infrastructure management costs and is now generating export earnings. More than three decades after its first invention, it is still undergoing development to meet stringent international demands. Over the years the Sheffel Bogie has steadily gained ground in the world marketplace and has now been adopted in parts of eastern Europe and south-east Asia.
The SAR owns the concept of the Sheffel Bogie as Sheffel was an employee of theirs, but he did receive professional recognition for his work. In 1975 he was awarded the Shell Prize for Industrial Design. In 1976, together with Dr Trevor Wadley (inventor of the Tellurometer), he received the Gold Medal of the Associated Scientific and Technical Societies of South Africa. The current owner of the technology is one of the SAR’s spin-off successors, Transnet, via its subsidiary, Transwerk.
So, next time you enjoy a comfortable, vibration-free ride on your local suburban train, think of Herbert Sheffel, the man who kept the SAR on track.
l Mike Bruton was the founding director of the Cape Town Science Centre, and is director of Imagineering at MTE Studios (www.mtestudios.com). He authored the book Great South African Inventions, published by Cambridge University Press.