Circle line (London Underground) with the other London Underground sub-surface lines: the Hammersmith & City line from Hammersmith to just before Aldgate; the Metropolitan line from Baker Street to Aldgate; and the District line from Tower Hill station to Edgware Road station. The line is electrified with a four-rail DC system: a central conductor rail is energised at and a rail outside the running rail at , giving a potential difference of . The running rails are not electrified. Much of the double track railway from the Hammersmith terminus to Westbourne Park station is on a high brick viaduct. East of Westbourne Park the
Distance between two straight lines equations of two non-vertical parallel lines the distance between the two lines is the distance between the two intersection points of these lines with the perpendicular line This distance can be found by first solving the linear systems and to get the coordinates of the intersection points. The solutions to the linear systems are the points and The distance between the points is which reduces to When the lines are given by the distance between them can be expressed as Distance between two straight lines The distance between two straight lines in the plane is the minimum distance between any