China Steel Corporation has announced the successful development of the first set of prestressed concrete sleepers in turnouts of torpedo car railway in Taiwan, based on the 3 million tonne online test since the installation into the railway in May 2010 year and the conformity with all design requirements.
A network of railroads is established in CSC to transport hot metal loaded in torpedo car with a gross weight over 550 tonnes, and bears 2.5 times of axle load in comparison with the conventional narrow gauge railway. CSC's rail tracks, besides, have to withstand a 250 ℃ heat impact radiated from the torpedo cars and to resist rainy climate as well as the particular environment in steel mill. As a result of the disadvantages, the service life of original wood sleeper was too short to meet the operational demand.
For the purpose of reducing the maintenance cost and to enhance the operational safety, CSC, in cooperation with Taiwan Technical University in 1995, has developed PC sleepers for the regular railway except those for turnouts due to higher loading capabilities and complicated specifications required. CSC, since then, has consumed a lot of manpower and expense to keep the total 113 sets of turnout systems working.
In recent years the surged environmental consciousness resulted in the deficiency of qualified wood sleepers and the PC sleepers, developed previously, performed satisfactory as well as the related technology advanced, therefore CSC started a new project for the research and development of PC sleepers in turnout for decreasing the maintenance frequency and the material cost further.
Evaluated by Raw Material Handling & In plant transportation department and Plant Engineering & Maintenance department of CSC, Dr chao lung Hwang professor of department of Construction Engineering, National Taiwan University of Science and Technology, was commissioned again in 2005 to form a task force. The team of professional members commenced the project from the on line digital investigation of tracks and turnouts in order to master their Dynamic behaviors and to specify the design requirements. The finished product was selected from 20 kinds of various sleeper configurations and concrete mixtures, passed 3 million cycle repeated load fatigue test, and expected to have 25 year service life minimum.
In addition to prestressed steel wire ropes, the finalized sleepers consist of pozzolanic material to maximize the bond of aggregates, i.e. the strength of concrete, and specially formed steel fiber to minimize the brittleness. The sleepers, consequently, are possessed of not only wooden elasticity also concrete strength. Though this special concrete recipe contains much less cement and meets the current trend of Energy Saving and Carbon Reduction, its strength is still higher than 1,000 kilogram per square centimeter the best of domestic concrete products for the time being.
CSC indicated that after the successive accomplishments of PC sleepers for railroad tracks and turnouts respectively, the new era of torpedo car railway equipped with only PC sleepers came out, which also induced a maintenance cost down over TWD 30 million annually and gained benefits in safety promotion, environmental protection and cost control. Besides, domestic and foreign patent applications were handed in for protecting the intellectual property of the project and to verify CSC's specialized fields beyond steel making.
