London Underground coaching stock London Underground coaching stock In 1989, the first 'Steam on the Met' event took place, and London Underground, hired British Rail coaching stock for the excursions. It was found that it was actually cheaper to buy the coaches instead of hiring them. Thus, London Underground has acquired numerous former British Rail coaching stock for these special excursion trains on the Metropolitan line, usually hauled by either steam locomotives, or the preserved electric locomotive No. 12 "Sarah Siddons". The fleet consisted of several Mark 1 and Mark 2 vehicles, and eight former British Rail Class 438 electrical multiple unit trailer set
Distance between two straight lines Distance between two straight lines The distance between two straight lines in the plane is the minimum distance between any two points lying on the lines. In case of intersecting lines, the distance between them is zero, because the minimum distance between them is zero (at the point of intersection); whereas in case of two parallel lines, it is the perpendicular distance from a point on one line to the other line. Because the lines are parallel, the perpendicular distance between them is a constant, so it does not matter which point is chosen to measure the distance. Given the