The length of railway to be constructed between London and Birmingham was 112½ miles. The line crossed a series of low-lying districts separated from each other by considerable ridges of hills; and it was the object of the engineer to cross the valleys at as high, and the hills at as low, elevations as possible. The high ground was therefore cut down and the “stuff” led into embankments, in some places of great height and extent, so as to form a road upon as level a plane as was considered practicable for the working of the locomotive engine. In some places, the high grounds were passed in open cuttings, whilst in others it was necessary to bore through them in tunnels with deep cuttings at each end. The most formidable excavations on the line are those at Tring, Denbigh Hall, and Blisworth. The Tring cutting is an immense chasm across the great chalk ridge of Ivinghoe. It is 2½ miles long, and for ¼ of a mile is 57 feet deep. A million and a half cubic yards of chalk and earth were taken out of this cutting by means of horse-runs and deposited in spoil banks; besides the immense quantity run into the embankment north of the cutting, forming a solid mound nearly 6 miles long and about 30 feet high. Passing over the Denbigh Hall cutting, and the Wolverton embankment of 1½ mile in length across the valley of the Ouse, we come to the excavation at Blisworth, a brief description of which will give the reader an idea of one of the most difficult kinds of railway work. [Picture: Blisworth Cutting]