Test Methodologies for Approving and Homologating Railway Sleepers (Ties) 2007-01-2959
Transportation has been understood today as an essential activity in the life of people all around the world. The efficiency of the transport systems is an indicator of the development and life quality of a nation. Each one of the diverse modalities of transport systems has inherent characteristics, being in competition each other with their advantages and disadvantages, depending upon the demand and framework available.
Among the main modalities used as a mean of transportation are the Highway Modal, the Railway Modal, the Naval Modal and the Aerial Modal. It is opportune to note that the Railway Modal becomes necessary as much in passenger as in freight transportation, being a very important logistic link for the economy of a country with a large territory, a great agricultural production and high concentration of people in urban areas. That is the case of Brazil.
Although the importance of others means of transportation for the brazilian economy and for life quality of the population, we can emphasize some of the advantages which the Railway Modal presents upon the others.
Once the railway has a technological characteristic of low friction as a result of the rolling of steel on steel, it offers the possibility of forming long convoys, drawn by an unique power unit, which provides great energy saving.
With the high speed of nowadays trains, one may run long distances in short time, carrying a high number of passengers and high weight of freight by just a lower cost.
Concerning to Metro transportation, a branch of Railway Modal, besides better comfort and safety provided to the passengers, it also offers efficiently quickness and punctuality, what is something not easily available with traditional Highway Modal in big cities.
In spite of the diverse positive aspects it presents, the railway in Brazil still can not compete with other Modals, mainly with the Highway Modal, because the maintenance costs of a railway specially concerning to the track are very much expensive, besides the fact they must be held by the own companies, in opposition to the Highway Modal in which Government has much of the responsibility, except in the case of private highways.
Thus taking in account this typical trait of the railway in Brazil by assuming the expenses ofthe maintenance of the track, some research centers, universities and manufacturers have been working on the development of diverse materials and railway components with the purpose of minimize all these costs and make this modal more competitive.
The Centro de Tecnologia da UNICAMP responding to the increasingly preoccupation of consumers in buying products with a better quality, lacking of defects and in accordance with standards and technical specifications has been actuating in the railway market by one of its departments, the DESF (Departamento de Engenharia de Sistemas e Ferroviária). Laboratory tests have been performed by using the facilities of the system of programmed load application, consisting of diverse servo-hydraulic actuators, with capacities up to 40 ton, providing the simulation of actual situations of loading with controlled efforts in the three directions, longitudinal, vertical and lateral.
Static and dynamic (fatigue) mechanical tests are performed in the laboratory on assemblies, components and special devices used by railway and metro companies in order to attest their quality in attending the requirements of standards and technical proceedings such as CEN, AREMA, Eisenmann Method and/or specifications of manufacturers and customers.
Among the many products already tested by the DESF is the sleeper (tie), which is the purpose of the present work, which will emphasizes the test methodologies, the standards for these tests and implications for the homologation of the railway component named sleeper (tie).