Book II. RAILROADS. 61:J 



broken small, as above describetl, being angular, will fasten together. In this way a road, when once well 

 made may be preserved in constant repair at a small expense. 



3778. Partial wetalling. Where the breadth of that part of a road, which alone has been formed of 

 hard materials, and over which the carriages commonly pass, is less than eighteen feet, it must be widened 

 with layers of broken stones to that breadth, first digging away the earth, and forming a bed for them with 

 pavement and broken stones at least ten inches deep. Near large towns the whole breadth of the road- 

 way should be covered with broken stones. 



3779. All labour by day taages ought, as far as possible, to be discontinued in repairing roads. The 

 surveyors should make out specifications of the work of every kind that is to be performed in a given 

 time. This should be let to contractors; and the surveyors should take care to see it completed according 

 to the specifications, before it is paid for. Attention to this rule is most essential, as in many cases not 

 less than tv/o thirds of the money usually expended in day labour is wasted. 



3780. The best seasons for repairing roads are generally considered to be autumn and 

 spring, when the weather is moist rather than otherwise. 



3781. B. Farey prefers laying on gravel vchen the road is in a moist state, immediately after the road has 

 had a scraping, in consequence of there being upon the surface of the road a small quantity of dirty matter 

 and broken gravel, which then form a sort of cement for the gravel to fix in. 



3782. Walker considers the best season for repairing roads to be the spring or very early in the summer, 

 when the weather is likely neither to be very wet nor dry ; for both of these extremes prevent the mate- 

 rials from consolidating, and therefore cause waste, and at the same time either a heavy or a dusty road : 

 but if done at the time he has recommended, the roads are left in good state for the summer, and become 

 consolidated and hard to resist the work of the ensuing winter. 



3783. The seasons for repairing preferred by Paterson are also spring and autumn. " Although it is 

 proper," he says, " at all times of the year, to put on a little metals whenever any hole makes its appear- 

 ance, yet in the drought of summer this will seldom be necessary. In summer, the roads are less liable 

 to cut ; but if, at some places, a little fresh metals may be necessary, no more should be put on than are 

 barely suflficient to bring those holes to the level of the rest of the road. Metals that are put on in the 

 drought of summer do not soon bind together. Until such timfe as there is rain sufiicient to cause them 



to bindj they will keep shifting and rolling about, and make a very unpleasant road to travel on. The 



most'^'lrt'o])er times of the ^ear to put on any quantity of metals are about the 



as they always bind best when the road is neither too wet nor too dry. "When they are put on about" the 



le months of October and April, 



month of October, they become firm before winter j and with a little constant attention, the road will be 

 easily kept in good order until the spring : and if it has been the case that the road has not been sufficiently 

 attended to during the winter, and that it has got into a bad state towards the spring, by putting on fresh 

 metals about the month of April, sufficient to bring it ihto smooth surface order, it will be very easily kept 

 in this good state throughout the summer." 



3784. M'Adam, on being asked, " Would you prefer repairing old roads in dry weather or in wet 

 weather?" answers: " In wet weather always; I alyrdys prefer mending a road in weather not 

 very dry." ; 



Sect. VII. Bailroads. 



3785. Tiaihvays or tramroads are not intended to be considered here as connected 

 with mnics, canals, or other works which come directly under the province of the 

 higher branches of engineering ; but merely as substitutes for the whole or a part of 

 the metalled surface of common roads. The necessity of an expeditious and cheap 

 mode of conveying coals from the pits to tite ships had, as early as the year 1676, intro- 

 duced the use of wooden railways for the waggons to move upon between the Tyne 

 river and some of the principal pits ; and these by degrees became extended to a great 

 number of other coal-works. They were first solely employed for transporting coals to 

 a moderate distance from the pits, to the places where they could be shipped, being 

 universally made of wood. By degrees they were, however, carried to a farther extent ; 

 the scarcity of wood, and the expense of their repairs, suggested the idea of employing 

 iron for the purposes of improving these rOads. At the first, flat roads of bar iron were 

 nailed upon the original wooden rails, or, as they were technically called, sleepers ; and 

 this, though an expensive process, was found to be a great improvement. But the wood 

 on which these rested being liable to rot and give way, some imperfect attempts were 

 made to make them of cast iron ; but these were found to be liable to many objections, 

 until the business was taken in hand by Outram, an engineer at B utterly Hall, Derby- 

 shire, who contrived, at the same time, so far to diminish the expense, and improve the 

 strength of the road, as to bring them to a degree of perfection that no one who has 

 not seen them can easily conceive could have been done. This having jbeen carried 

 into execution in a few eases, and found to answer, iias been improved upon and sim- 

 plified by practice, till it is now brought tp siich a state of perfection as to have given 

 proofs that it admits of being carried iuch beyond the limits, of what was for many 

 years conceived to be possible, and to afford demonstrative evicte^ce that it may be in 

 future employed to a wider extent btill, to which no limits can be. at present assigned or 

 foreseen. - '* 



3786. Railways are of three kmds,} flat, edgedj and suspension railways. The flat 

 railway is composed of pieces of timber, four bt five' irfChes square, called rails; or of 

 pieces of cast iron, of about four inches in breadth, and one or more inches in thickness, 

 according to tlie weight they are to carry. The edge rail is formed of pieces of cast or 

 wrought iron (the latter is now generally preferred), with a ledge or flanch rising at 

 right angles in the inner side of the rail. The flat rails are generally laid on pieces of 

 timber called sleepers, and the edge rails on solid blocks of stone, from nine to twelve 

 inches in thickness. The suspension rail consists of a line of vertical edge, elevated on 

 posts ; across this line tlie load is placed, like the panniers on the back of a horse, by a 

 suitable contrivance for diminishing friction, and adjusting the weight so as it may be 



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