4 feet 8.5 inches. And so
the first tramroads were laid down of this gauge. The tools and
machinery for constructing coal-waggons and locomotives were formed with
this gauge in view. The Wylam waggon-way, afterwards the Wylam
plate-way, the Killingworth railroad, and the Hetton rail road, were as
nearly as possible on the same gauge. Some of the earth-waggons used to
form the Stockton and Darlington road were brought from the Hetton
railway; and others which were specially constructed were formed of the
same dimensions, these being intended to be afterwards employed in the
working of the traffic.

As the period drew near for the opening of the line, the question of the
tractive power to be employed was anxiously discussed. At the Brusselton
incline, fixed engines must necessarily be made use of; but with respect
to the mode of working the railway generally, it was decided that horses
were to be largely employed, and arrangements were made for their
purchase. The influence of Mr. Pease also secured that a fair trial
should be given to the experiment of working the traffic by locomotive
power; and three engines were ordered from the firm of Stephenson and
Co., Newcastle, which were put in hand forthwith, in anticipation of the
opening of the railway. These were constructed after Mr. Stephenson's
most matured designs, and embodied all the improvements which he had
contrived up to that time. No. I. engine, the "Locomotion," which was
first delivered, weighed about eight tons. It had one large flue or tube
through the boiler, by which the heated air passed direct from the
furnace at one end, lined with fire-bricks, to the chimney at the other.
The combustion in the furnace was quickened by the adoption of the
steam-blast in the chimney. The heat raised was sometimes so great, and
it was so imperfectly abstracted by the surrounding water, that the
chimney became almost red-hot. Such engines, when put to their speed,
were found capable of running at the rate of from twelve to sixteen miles
an hour; but they were better adapted for the heavy work of hauling
coal-trains at low speeds--for which, indeed, they were specially
constructed--than for running at the higher speeds afterwards adopted.
Nor was it contemplated by the directors as possible, at the time when
they were ordered, that locomotives could be made available for the
purposes of passenger travelling. Besides, the Stockton and Darlington
Railway did not r