But the necessities of commerce could not be denied, and the following year the bill came up again, and was passed. Stephenson, as principal engineer of the railway, at once began its building. This in itself was a unique and very remarkable feat. An immense bog, called Chat Moss, had to be crossed, and Stephenson was the only one of the engineers concerned who did not doubt whether such a crossing were really possible. Ditches that were dug to drain the bog immediately filled up; as soon as one part was dug out the bog flowed in again; it swelled rapidly in rainy weather, and piles driven into it would sink down into the mire. But Stephenson finally built his road across it. A matting of heath and the branches of trees was laid on the bog’s surface, and in some places hurdles interwoven with heather; this floating bed was covered over with a few inches of gravel, and on this the road proper was constructed. In addition to the crossing of Chat Moss a tunnel of a mile and a half had to be cut under part of Liverpool, and in several places hills had to be leveled or cut through. The old post-roads had never had to solve such problems, and George Stephenson deserves to rank as high as a pioneer of railroad construction as he does as builder of the working locomotive. The directors of the railway were anxious to secure the best engine possible, and opened a general competition, naming certain conditions the engine must fulfil. Stephenson and Henry Booth built the “Rocket,” and, as this was the only engine that fulfilled all the conditions, took the prize. The “Rocket” was by far the most perfect locomotive yet built, having many new improvements that Stephenson had recently worked out. The “Rocket” would make thirty miles an hour, a wonderful achievement, and was put to work drawing the gravel that was used in building the permanent road across Chat Moss. With the aid of such a powerful engine the work went on more rapidly, and in June, 1830, a trial trip was made from Liverpool to Manchester and back. There was a huge gathering at the stations at each end of the line. The train was made up of two carriages, filled with about forty passengers, and seven wagons loaded with stores. The “Rocket” drew this train from Liverpool to Manchester in two hours and one minute, and made the return trip in an hour and a half. It crossed Chat Moss at the rate of about twenty-seven miles an hour.