312 



CONSTRUCTION OF THE LINE. 



CHAP. XV. 



m 



The length of railway to be con- 

 structed between London and Bir- 

 mingham was 112^- miles. The line 

 crossed a series of low-lying districts 

 separated from each other by con- 

 siderable ridges of hills ; and it was 

 the object of the engineer to cross 

 the valleys at as high an elevation, 

 and the hills at as low a one, as 

 possible. The high ground was there- 

 fore 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 work- 

 ing of the locomotive engine. In 

 some places, the high grounds were 

 passed in open cuttings, as at the 

 Oxhey summit near Harrow, Duds- 

 well, Tring, Denbigh Hall, and Blis- 

 worth ; whilst in others it was neces- 

 sary to bore through them in tunnels 

 with deep cuttings at either end, as at 

 Primrose Hill, Watford, and Kilsby. 



The most formidable excavations 

 on the line are those at Tring, Den- 

 bigh Hall, and Blisworth. The Tring 

 cutting is an immense chasm across 

 the great chalk ridge of Ivinghoe. 

 It is two miles and a half long, and 

 for a quarter of a mile is fifty-seven 

 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 



