A MARVEL OF MECHANISM.
“The time is coming when it will be cheaper for a working man to travel
on a railway than to walk on foot.”
So prophesied George Stephenson some few years before his successful
competition at Rainhill; and by his success on that fateful day, he had
brought the time appreciably nearer. The directors of the Liverpool
and Manchester Railway no longer debated as to what form of traction
they should adopt.
But Stephenson did not rest on his laurels. Every new engine showed
some improvement. The “Arrow” sped over Chat Moss at about 27 miles an
hour, on the occasion of the first complete journey along the line, on
the 14th of June, 1830; and when, on the public opening of the railway
on the 15th of September, 1830, Mr. William Huskisson, M.P., was
unhappily knocked down by the “Rocket,” George Stephenson himself took
the maimed body in the “Northumbrian,” fifteen miles in twenty-five
minutes—that is, he drove the engine at the speed of thirty-six miles
an hour.
The sad death of Mr. Huskisson has often been referred to, but we
may tell the story again, following the account given by Mr. Smiles,
who had the advantage of the assistance of Robert Stephenson in the
preparation of his biography.
The engines it appears halted at Parkside, some seventeen miles from
Liverpool, to obtain water. The “Northumbrian,” with a carriage
containing the Duke of Wellington and some friends, stood on one
line, so that all the trains might pass him in review on the other.
Mr. Huskisson had descended from the carriage and was standing on the
rail on which the “Rocket” was rapidly approaching. There had been
some coolness between the Duke and Mr. Huskisson, but at this time the
Duke extended his hand and Mr. Huskisson hurried to grasp it, when the
bystanders cried “Get in! get in.”
Mr. Huskisson became flurried and endeavoured to go round the carriage
door which was open and hung over the rail; but while doing this, the
“Rocket” struck him and he fell, his leg being doubled over the rail
and immediately crushed. Unfortunately he died that evening at Eccles
Parsonage.
This sad event cast a gloom over the otherwise rejoicing day; but
the wonderful speed at which the wounded man was conveyed, proved a
marvellous object lesson as to what the locomotive could accomplish.
In the “Planet,” put upon the line shortly after the opening, the
cylinders were placed horizontally and within the fire box. The engine
drew eighty tons from Liverpool to Manchester against a strong wind
in two and a-half hours, while on another occasion with a company of
voters, it sped from Manchester to Liverpool, thirty-one miles, in an
hour. But next year the “Samson,” which was still further improved,
and the wheels of which were coupled so as to secure greater grip on
the rails, hauled 150 tons at twenty miles an hour with a smaller
consumption of fuel.
The locomotive had now become one of the wonders of the world. Since
then its speed has been doubled. But all the improvements (with
possibly one exception—that of the compound cylinder which is at
present only partially in use) have been more in details than in
principles. Thus the 70 or 80 ton express engine, which covers mile
after mile at the rate of a mile a minute without a wheeze or a groan,
is not very different essentially from George Stephenson’s locomotives,
though its steam pressure is very much higher.
There are, for instance, the multitubular boiler, the furnace
surrounded by water and communicating with the boiler, the horizontal
cylinders acting directly on the driving wheels, and the steam-blast by
which the waste steam is spouted up the chimney, creating a draught in
the furnace.
These may be regarded as the more important of the essential
principles, although there is diversity of details, more especially
for the different work required. But the steam pressure is now much
greater. Let us glance at a typical English locomotive. You might not
think it, but the machine has about five thousand different parts, all
put together as Robert Stephenson said “as carefully as a watch.”
At first sight you will probably not see the cylinders. The tendency
in many engines now seems to be to place them inside the wheels, for
it is urged that the placing of the heavier parts of the mechanism
near to the centre lessens oscillation, and protects the machinery
more effectually. Against this, it is said that the placing of the
cylinders in that position increases the cost and the complication of
the driving axle, and renders the pistons and valves more inaccessible
for the purposes of repair. Both forms have their advocates, and the
outside-cylinder form may be seen on the London and South-Western and
some other railways, while the inside may be seen on the North-Western
and others.
The boiler is of course the long, round body of the locomotive, and
in English machines it is placed on a strong plate frame. Then as to
the driving-wheels. Express engines, such as the splendid “eight-feet
singles” of the Great Northern, have often, as the name implies, but
one large driving-wheel on either side, and for great speeds this form
is held to possess certain advantages. Certainly the performances of
Mr. Patrick Stirling’s expresses would indicate that this is the case.
With steam raising the safety valve at a pressure of 140 lbs. to
the square inch, the engines will whisk a score of carriages out
of King’s Cross up the northern height of London at forty miles an
hour, and then without a stop rush on to Grantham at near sixty.
Standing on the platform at King’s Cross, with a large part of the
immense driving-wheel hidden below you as it rests on the rail, you
do not realise its tremendous size. Yet, let the engine-driver open
the throttle, as it is called—that is, turn on the steam to the
cylinders—and that huge wheel will revolve, and with its neighbour on
the other side, haul after them that heavy train of carriages, and,
gathering speed as they go, they will soon be rushing up the incline at
forty miles an hour, and then on at sixty. It is a marvel of mechanism!
But then the compound engines that Mr. F. W. Webb, the engineer of the
North-Western, builds for that Company can also perform remarkable
things. The compound is the great modern improvement (some engineers
might doubt whether improvement be the correct word) in the locomotive,
effecting, it is said, an economy of from ten to fifteen per cent.
in fuel. Now the compounding principle has been developed to such an
extent in marine steam engines that it revolutionised steam navigation.
But the application of the principle has not been so great in the case
of the locomotive.
Briefly, the principle is this—the steam is sent out from the boiler at
a high pressure, say 160 to 180 lbs. to the square inch, and is used
in one or in a pair of high-pressure cylinders, and then used again,
by means of its expanding power, in a larger, low-pressure cylinder.
Mr. John Nicholson, of the Great Eastern Railway, suggested a compound
locomotive before even the compound marine engine had been made, and
his design was successful; but in 1881 Mr. Webb, of the North-Western,
patented a compound locomotive, with two small high-pressure, and one
large low-pressure cylinders, the latter twenty-six inches in diameter.
Placed between the front wheels, the bright boss of this cylinder may
be seen in shining steel as it flies over the rails.
The argument is that the compound burns less fuel and is more powerful
than a non-compound of the same weight; but against this is launched
the objection that the compound is more expensive to build, to repair,
and to maintain. Still further it is argued, that a fast-speeding
locomotive has not the time in its hurrying life to expand its steam in
the tick of time between each stroke of the piston.
[Illustration:
THE COMPOUND LOCOMOTIVE “GREATER BRITAIN.” _By kind permission of Mr.
F. W. Webb, L. & N. W. Railway._ ]
Mr. Worsdell’s compounds on the North-Eastern Railway have but two
cylinders, one high and the other low-pressure. The one is eighteen and
the other twenty-six inches across. Instead of the steam alternating
between the two cylinders, it all passes first to the high-pressure
and then, through a pipe in the smoke-box, to the larger low-pressure
cylinder. These locomotives, it is said, are not under the objection
alleged against the other compounds—viz., that they have more parts,
and are more costly to build and maintain. Yet it is claimed for them
that they are more economical and more powerful than non-compounds.
When doctors disagree who shall decide? The cost or speed might decide;
but at present it seems doubtful on which side the balance does
really fall. Engines of the three types have done splendid work. A
Worsdell compound, built by Mr. Worsdell, of the North-Eastern Railway,
is reported to have rushed down the incline to Berwick one day at
seventy-six miles an hour for some miles at a time. Then the “Greater
Britain,” a massive North-Western compound engine, turned out at the
Crewe works in 1891, and weighing seventy-five tons, can whirl along
with ease a heavy twenty-five coach express at an average of over fifty
miles an hour, with a comparatively small consumption of fuel.
This locomotive was described in the _Engineer_ newspaper as the most
remarkable that had been built in England for several years. Its axle
bearings are of great length, and its parts are very substantial,
so that it ought to keep out of the repairing shops for long spells
of time. It was specially planned for both fast and heavy passenger
traffic to Scotland, and its work on its trial trip was so good that it
was confidently expected it would answer expectations. In working, the
engine has been found to develop great speed and power, easily running
at over fifty miles an hour with what is called a double train—viz.,
twenty-five coaches, behind it. Indeed, it has run at fifty-five
miles with this heavy train. Its stated speed ranges from thirty to
fifty-five miles an hour, with a low consumption of fuel.
This last is a matter of very great importance to engineers and railway
directors; and when we state that, according to Mr. Bowen Cooke, the
North-Western engines altogether burn 3095 tons of coal per day, any
small saving per hour would be eagerly welcomed.
Now, it is claimed that the compounds have consumed about six pounds
of coal per mile less than others on the same work, and that they also
haul along loads which would require two of the other type. If so, the
saving in the North-Western coal-bill must be enormous.
[Illustration: BACK AND FRONT VIEW OF THE LOCOMOTIVE “GREATER BRITAIN.”]
A great feature in this engine is a combustion chamber placed within
the barrel of the boiler. This chamber catches all the gases from the
furnace, and causes the heat generated by them to be used to the utmost
for the production of steam. Though heavier than any engine previously
built, yet it is so made that no greater weight than usual rests upon
any of the wheels, thus throwing no extra strain on the railway or
the bridges. The two couples of driving-wheels are placed before the
furnace, and an additional couple of small wheels behind the furnace,
and beneath the foot-plate where the driver and fireman stand. The
weight therefore is evenly distributed, with another pair of wheels to
bear the burden. The front wheels are fitted with the radial axle-box
patented by Mr. Webb, so that, although the engine is of great length,
yet it can speed round curves with perfect safety.
Yet this engine, though one of the most remarkable developments of the
locomotive, is in essence and in principle but very like the “Rocket.”
The difference lies in its innumerable details, exhibiting so much
engineering skill and ingenuity, in the compound cylinders, in higher
pressure steam, and in its marvellous power and speed combined.
On the other hand, the Great Northern runs daily from Grantham to
London at fifty-three and fifty-four miles an hour average; while it
was reported in the _Engineer_ of the 10th of March, 1888, that a Great
Northern train from Manchester to London, when running from Grantham to
London, covered one mile in forty-six seconds, that is, at the rate of
seventy-eight and a-quarter miles an hour, and two miles following each
other were run in forty-seven seconds each, that is, seventy-six miles
an hour. We doubt, indeed, if any railway in the world can show regular
faster daily running than some of the Great Northern expresses between
London and Grantham. The average speed of their Manchester train over
this ground is slightly over fifty-four miles an hour. Then there are
the Great Western expresses, the “Dutchman” and the “Zulu,” at only
slightly less speeds, to say nothing of the fine performances of the
Midland. We may take it, therefore, that the compound locomotives,
excellent as their work has been, have not really beaten their rivals
in point of speed.
Compounds are used largely on the North-Western, the Great Eastern,
and the North-Eastern, and should they prove to be really more
economical in working, while maintaining at least equal power and speed
with their rivals, we have no doubt but that they will prevail.