Actually in traction transmission line we use two phase system...aap agar traction tower line ko dekhenge to aapko 2 phase system dikhega... infact more precisely two phase double circuit system...
Thank you very much for nice and valuable information, I am a non engineering person but highly interested in such tyle of engineering subjects, I am always confused that how electric supply managed in long distance lines, suppose from Delhi to Mumbai, definitely there must be different sources, please explain.