Using new analytical algorithm to study the effect of temperature variations on static shape of contact wire of OCS

The vibrations of pantograph passing underneath the overhead system can be reduced by using droppers to place the contact wire in the designed curve. Nowadays, various software programs are used to estimate dynamic interaction of pantographs and overhead catenary system. In order to implement the software program, the necessary static force for each dropper should be estimated initially to place the contact wire in the designed curve. Unlike most available software programs, the implemented software program in this research consists of a heuristic analytical algorithm to estimate the static shape of the overhead catenary system. Accordingly, the variable separation and eigen function expansion method were used to calculate the static shape of contact wire and messenger cable under a given loading condition. At the next step, the stiffness matrix of contact wire in catenary was obtained and a procedure was defined to calculate the necessary static force for each dropper, which would then place the contact wire in the target curve. Finally, effort was made to examine the function of automatic tension device in OCS (Tension Wheel considering the Coulomb’s friction). Moreover, the deformations in the contact wire and messenger cable due to temperature changes were estimated and the results shows that allowable friction in the tension wheel can cause 27 % deviation in sag of the contact wire