Quite to the contrary, copper is the usual material used (either pure, or slightly alloyed to improve tensile strength and abrasion behaviour and things like th

Quite to the contrary, copper is the usual material used (either pure, or slightly alloyed to improve tensile strength and abrasion behaviour and things like that without compromising too much on copper's superior electrical conductivity, though that extra tensile strength is only really important for high speed railways – conventional railways could perfectly get by on pure copper alone). Sag is solved by tensioning the wire and using a catenary wire for additional support between poles, and eventual abrasion of the wire is just a fact of life for electric railways.