Wherever there is a uniform gauge, the cleciring•house system is acted upon by the railway companies, to the obvious advantage of all parties. The principle of the system is, that passengers shall be booked through at all principal stations, and conveyed to their desti nation without change of carriage; that horses and cattle be in like manner carried through without change of conveyance, and goods without being shifted or re-assorted ; that the companies respectively shall pay a fixed rate per mile for such carriages and waggons, not their own property, as they may ase, and a further sum per day by way of fine or demur rage for detention, if kept beyond a prescribed length of time ; and that all traffic accounts between the several companies shall pass through the Clearing-House.
The carriages used on railways we need not stop to describe ; every one has had more or less opportunities of noticing the gradual improvements introduced. The wonder working locomotive, however, must engage a little of our attention.
In a modern' locomotive, the tubes through the boiler, for the passage of flame and heated air, are now always made of brass, which is found much more durable than copper. They vary in number in different engines from about ninety to a hundred and fifty or upwards, being frequently less than an inch and a half in diameter. The power of generating steam, which is the measure of efficiency in a loco motive engine, depends much upon judicious tubing. Boilers are frequently tubed to such an extent that from four to six hundred square feet of heated metal is exposed to the water, in addition to the area of the fire box itself: An important feature in a locomotive boiler is its security from bursting, because as the tubes are much weaker than the external casing of the boiler, they are almost certain to give way first; and the bursting of one or two tubes is rarely productive of more serious consequence than extinguishing the fire, and thereby causing a gradual stoppage of the machine. In the old engines the cylinders were placed at the bottom of the smoke-box, and the machinery under the boiler ; but there is a growing preference for those in which the cylinders are fixed outside the framing, and the power is conveyed to the wheels by ex ternal cranks and connecting-rods. The long boiler' engines of the narrow gauge are very large; but those of' the Great Western Com pany are still more so. One of the engines of this company has about 1750 square feet of heating surface in the boiler ; has cylinders of 18 inches diameter and 24 inches stroke; driving-wheels of 8 feet diameter; and two pair of bearing-wheels of 4 feet 0 inches in diameter. The total length is 24 feet ; the distance between the supporting wheels 16 feet ; the weight of the engine alone, without fuel or water 281 tons, and of the tender, 10 tons ; and the total weight of engine and tender when loaded, about 50 tons. These engines, in the express train between London and Exeter, go at a speed, in some parts, of dO miles an hour.
Small and light locomotives have been re cently introduced, fitted for the traffic of branch lines.
Taking one line of railway with another, main lines with branch lines, and passenger traffic with goods traffic, it is found that one locomotive is required for about every two miles of railway ; to work all the traffic effectively, and to have a sufficient reserve store for contingencies. We are thus enabled
to form a rough estimate of the number of locomotives in the United Kingdom.
Rope traction on railways is becoming gra dually abandoned; and the once highly ex tolled Atmospheric traction is only applied on two miles of the Dublin and Kingstown Rail way.
We will next take a rapid glance at the statistics of railways. The first railway esta blished in this country as a distinct underta king, and intended for public use, was the Surrey Iron Railway, the company for which was incorporated in 1801. In the following twenty years only twenty new railway compa nies were incorporated ; but the Stockton and Darlington Railway, the act for which passedp after much opposition, in 1821, gate an im pulse to this kind of enterprise. Between 1801 and 1840 there were 290 aots passed relating to railways. These sanctioned the construction of about 3000 miles of railway ; but many of the schemes were afterwards abandoned. Down to 1840 about 1100 miles of railway were finished and open, and about 60,000,0001. had been expended on them. Between 1840 and 1850, railway legislation presented the following results :— Year. Acts. Length.
1841' 19 14 miles.
184.2 22 67 „ 1843 - 24 91 1844 48 707 „ 1845 12b 2883 „ 1840 270 4700 „ 1847 184 1003 „ 1848 83 800 „ 1849 85 50 „ 1850 36 50 „ - 841 10,705Taking the earlier acts at 299, and mileage at 3000, we have 0 total of 1140 acts of parlia went sanctioning railways, and about 13,700 miles of railway so sanctioned. This in cludes the lines which have been abandoned. At the end of 1849 the length of railway open for traffic in the United Kingdom was 5996 miles; at the end of 1850 it was 0621 miles. This last amount is made up as follows :— England and Wahl 5132 tulles.
Scotland 951 „ Ireland 538 „6621 The average receipts per mile in England and Wales, during 1850, for passengers was 1218/., and for goods 1110/.; this shows that the goods traffic has nearly reached the level of the passenger traffic. The passengers conveyed in the year ending Rine, 1850 were 60,840,175 ; who paid fares amounting to 6,465,575/. It is a curious fact that the ave rage paid by all passengers, of all classes, for all journeys, on all the railways, remains every year pretty nearly equal in amount, viz. two shillings per journey ; this is much smaller than most persons would have expected, and it shows how much the short or local traffic preponderates over the long or through traffic. The goods traffic in the same twelve months brought 5,042,2771.; giving with the passengers' receipts the astonishing sum of 12,407,8521.--exceeding one million sterling per month. There is every reason to believe that the year 1851 will show a very notable increase on these numbers.
Among foreign countries, America, Prussia, Germany, Belgium, and France have not been slow to imitate the railway proceedings of England. On the first day of 1851, the United States had 8707 miles of railway, which cost about 60,000,0001. On the conti nent of Europe the system is making rapid strides, but not comparable to that of the United States.
It is satisfactory to know that the Great Exhibition contains specimens of the latest and finest constructions relating to railway machinery.