The life of George Stephenson, railway engineer - Lighthouse ...

332 LIFE OF GEORGE STEPHENSON. [chap. xxvn.
that has been the cause of the upper part throwing a little more
pressure upon the invert." As Mr. Stephenson had promised,
the invert was put in ; the tunnel was made perfectly safe ; and
the traffic began to be carried over the entire length of the line
early in the year 1841, and has continued without interruption
ever since.
In 1838, Mr. Stephenson was acting as engineer for the
Blackwall Railway, in conjunction with Mr. Bidder. In their
united report of that year we find them recommending stationary
engines for the working of that line, as being the more safe and
economical, principally on the ground of the sharpness of the
curves, the steepness of the gradients, and the shortness of the
railway. Subsequent experience, however, of the powers of the
locomotive, and of its economy in working as compared with
fixed engines, induced the eventual abandonment of the latter
power in favour of the former. It is worthy of notice that Mr.
Stephenson, who was always ready to adopt improved modes of
working railways, employed the electric telegraph at a very
early period to regulate the working of that line ; indeed, he
was one of the first of the railway engineers who recognized its
advantages for this purpose.
The North Midland Railway was a favourite line of Mr.
Stephenson's for many reasons. Its works were of a formidable
character ; it passed through a rich mining district, in which it
opened up many valuable coal-fields, and it formed part of the
great main line of communication between London and Edin-
burgh, on the completion of which, by the East Coast line
through Newcastle, Mr. Stephenson had anxiously set his heart.
The North Midland Railway was originally projected by gentlemen
interested in the London and Birmingham line. The inten-
tion was to carry the latter railway from Rugby to Leeds ; but,
finding themselves anticipated in part by the projection of the
Midland Counties line from Rugby to Derby, they confined
themselves to the district between Derby and Leeds. The pror
jectors appointed Mr. Stephenson to examine the country, and
lay out the best line ; and after a careful and laborious investi-
gation, in which he was ably assisted by his pupil Mr. Swanwick,
he reported the result to a public meeting held at Leeds, in