opened the gate wide for the monster, as he thought, and on being asked
what was to pay, said "Na-na-na-na!" "What have we got to pay?" was
again asked. "No-noth-nothing to pay, my dear Mr. Devil; do drive on as
fast as you can!" This, one of the first steam carriages, reached London
in safety, and was exhibited in the square where the large station of
the London and North-Western Railway now stands. Sir Humphrey Davy took
great interest in it, and, in writing to a friend, said: "I shall hope
soon to see English roads the haunts of Captain Trevethick's dragons."
The badness of roads, however, prevented its coming into general use.

Trevethick in 1804 constructed a locomotive for the Merthyr and Tydvil
Rail in South Wales, which succeeded in drawing ten tons at five miles
an hour. The boiler was of cast-iron, with a one-cylinder engine, spur
gear and a fly-wheel on one side. He sent the waste steam into the
chimney, and by this means was very nearly arriving at the blast-pipe,
afterwards the great and important discovery of George Stephenson. The
jumping motion on the bad roads, however, caused it constantly to be
dismounted, and it was given up as a practical failure, being sent to
work a large pump at a mine. Trevethick was satisfied with a few
experiments, and then gave it up for what he thought more profitable
speculations, and no further advances were made in locomotives for some
years. An imaginary difficulty seems to have been among the obstacles to
its progress. This was the supposition that if a heavy weight were to be
drawn, the grip or bite of the wheels would not be sufficient, but that
they would turn round and leave the engines stationary, hence Trevethick
made his wheels with cogs, which of course tended to cause great jolts,
as well as being destructive to the cast-iron rails.

A Mr. Blenkinsop of Leeds patented in 1811 a locomotive with a racked or
toothed rail. It was supported on four wheels, but they did not drive