Cod-liver Oil

Abstract

In the 1970s JR Japanese Railways after many years of maintenance observation realized that around 70% of installed sleepers from wood have a very short life time, this because the existing weather influences where leading to molding and rotting of wood. JR decided to develop alternative material so that life time of sleepers can be increased and track behavior advantages of wooden sleepers can be retained.The letters “FFU” stand for “fiber-reinforced foamed urethane”, the material used in Japan to develop a synthetic sleeper. Back in 1978, a company called Sekisui was awarded several prizes in Japan for this technological development, which initially went under the name of “Eslon Neo Lumber FFU”.FFU synthetic sleeper is from a material that has the same material properties as natural timber and can be handled and processed as easily as it can. The synthetic material has virtually the same specific mass as the natural one, yet a very considerably longer service life than the latter, and its weathering proper ties are also superior. In 1980, the Railway Technical Research Institute (RTRI), working in cooperation with the Japanese railways, laid sleepers made of this material on two experimental sections of track in Japan. Following on from a period of five years of practical experimentation, in which all the specified requirements were fulfilled, FFU has since then been used by the Japanese railways as a standard product on steel structures, under points and crossings and in tunnels in combination with both ballasted and ballast less track. In 1996, the RTRI removed the first synthetic sleepers from the experimental track sections and subjected them to a new series of tests. Extrapolating the results recorded at that time, FFU would be expected to have an in-situ service life of more than fifty years.Since 2004, railway sleepers made of FFU have been in use in Europe on railway bridges with open load-bearing structures made of steel as well as under points and crossings. In September 2008, Munich’s University of Technology wrote the final report on a research project into such sleepers, drawing positive conclusions. 2011 DB AG – German Railways installed first time FFU on a 60 m long bridge in Vilsbiburg. 2012 DB AG used FFU for two 60.000 t/day switches in Wurzburg [2].In 2011, 30 years after the first field test, RTRI again did laboratory test with sleepers removed from first field test. This 30 years old and under regular train operation used sleepers showed that the technical figures have been decreased a little. The conclusion of this test was that RTRI wrote a letter to JR – Japanese Railway operator – that they can still use these FFU sleepers for the next 20 years.