Dear Aspirant,

Standard Parallels are lines at which there is no distortion in the map projection. Standard parallels are used in both conical and cylindrical projections. They theoretically touch the earth's surface. Standard parallels are parallel lines that are drawn on a reference globe that will maintain a scale factor of 1.0 .

Whereas,

Standard Lines are a railroad line or route upon which the regular or highest rates apply : a fast-service route in distinction from slower and perhaps longer routes or from one that is partly by rail and partly by water — compare differential route.

Hope this helps.

Good Luck!