The Eastern railroad of Massachusetts connects Boston with Portland, in the state of Maine, by a line which is located close along the sea-shore. Between Boston and Lynn, a distance of eleven miles, the main road is in large part built across the salt marshes, but there is a branch which leaves it at Everett, a small station some miles out of Boston, and thence, running deviously through a succession of towns on the higher ground, connects with the main track again at Lynn; thus making what is known in England as a loop-road. At the time of the Revere accident this branch was equipped with but a single track, and was operated wholly by schedule without any reliance on the telegraph; and, indeed, there were not even telegraphic offices at a number of the stations upon it. Revere, the name of the station where the accident took place, was on the main line about five miles from Boston and two miles from Everett, where the Saugus branch, as the loop-road was called, began. The accompanying diagram shows the relative position of the several points and of the main and branch lines, a thorough appreciation of which is essential to a correct understanding of the disaster. The travel over the Eastern railroad is of a somewhat exceptional nature, varying in a more than ordinary degree with the different seasons of the year. During the winter months the corporation had, in 1871, to provide for a regular passenger movement of about seventy-five thousand a week, but in the summer what is known as the excursion and pleasure travel not infrequently increased the number to one hundred and ten thousand, and even more. As a natural consequence, during certain weeks of each summer, and more especially towards the close of August, it was no unusual thing for the corporation to find itself taxed beyond its utmost resources. It is emergencies of this description, periodically occurring on every railroad, which always subject to the final test the organization and discipline of companies and the capacity of superintendents. A railroad in quiet times is like a ship in steady weather; almost anybody can manage the one or sail the other. It is the sudden stress which reveals the undeveloped strength or the hidden weakness; and the truly instructive feature in the Revere accident lay in the amount of hidden weakness everywhere which was brought to light under that sudden stress. During the week ending with that Saturday evening upon which the disaster occurred the rolling stock of the road had been heavily taxed, not only to accommodate the usual tide of summer travel, then at its full flood, but also those attending a military muster and two large camp-meetings upon its line. The number of passengers going over it had accordingly risen from about one hundred and ten thousand, the full summer average, to over one hundred and forty thousand; while instead of the one hundred and fifty-two trains a day provided for in the running