zontal lines dividing the railway into sections, while the slanting lines represent the engines or trains timed to run over the line. Thus the diagram offers, as it were, a visible picture of the state of the line, as to its being occupied or otherwise, between any two points at any minute of the day, and it will be easily apparent that such diagrams are invaluable, and in fact indispensable, in arranging train alterations or the running of new trains or special trains when required. The section of line chosen for illustration is that between Liverpool and Manchester, upon the major portion of which there is as yet only one up and one down line of rails, and on this portion one train cannot pass another proceeding in the same direction, unless the first one takes refuge in a siding. Over this Liverpool and Manchester Railway there are running at the present time, for greater or less distances, no fewer than 272 passenger trains, and 292 goods trains, or a total of 564 trains up and down within twenty-four hours. Of the passenger trains, 112 are expresses, fourteen of which travel at a speed of forty-four miles an hour, and the remainder at an average speed of thirty-five miles an hour; and there are 56 express goods trains running at about twenty-three miles an hour.
Over certain busy portions of the North-Western system it has been found necessary, owing to the enormous development of the traffic, to lay down additional lines of rails, and there are now four lines (viz., two up and two down) between London and Roade, between Stafford and Crewe, and over some twenty shorter sections of railway, varying from half a mile to five miles in length, while, on other sections, a third line has been provided for goods traffic only. The advantages of the duplicated lines are obvious; they admit of the fast and slow trains being kept separate,
