About 1750, according to Nicholas Wood, cast-iron wheels were introduced; but in 1765 wooden wheels were still mostly used at the back of the waggon, to allow of the convoy getting a better grip when the waggon was going, by its own weight, down an incline; though even then the danger of accident was, as Buddle's observations suggest, sufficiently grave. On this same point it is said by T. S. Polyhistor, in a "Description of a Coal Waggon," given in the "London Magazine" for March, 1764:—
"They commonly unloose the horse when they come to the runs, and then put him too again when down; the reason of their taking him off at such places is because, were the convoy to break, it would be impossible to save the horse from being killed, or if the waggon-way rails be wet sometimes a man cannot stop the waggon with the convoy and where the convoy presses upon the wheel it will fire and flame surprisingly; many are the accidents that have happened as aforesaid; many hundred poor people and horses have lost their lives; for was there ever so many waggons before the waggon that breaks its convoy and has not got quite clear of the run, they are all in great danger, both men and horses, of being killed."
Polyhistor also states that the quantity of coal one of these waggons would draw on the rails was 19 "bolls," or "bowls," as he calls them. This gave a load of about 42 cwt. of coal, as compared with the load of 17 cwt., or less, to which the waggons on the ordinary roads at the collieries had been reduced. The advantage from the point of view of transport was obvious; but no less certain, also, was the risk to life and limb when a waggon with over two tons of coal was allowed to run down an incline checked only by a primitive wooden brake, with a man seated on one end of it to press it against a wheel. In wet weather boys or old men were employed to sprinkle ashes on the rails; but there were times when the rail-ways having a steep descent could not be used at all.
Introduced on the Tyne, the rail-way was adopted in 1693 by collieries on the Wear, and it also came into vogue in Shropshire and other districts. In 1698 a rail-way was set up on Sir Humphry Mackworth's colliery at Neath, Glamorganshire; but after it had been in use about eight years it was condemned by a grand jury at Cardiff as a "nuisance," and the portion crossing the highway between Cardiff and Neath was torn up. In a statement presented, rebutting the allegation of the grand jury, it was said: "These waggon ways are very common and frequently made use of about Newcastle and also at Broseley, Benthal and other places in Shropshire, and are so far from being nuisances that they have ever been esteemed very useful to preserve the roads, which would be otherwise made very bad and deep by the carriage of coal in common waggons and carts."
The Tyneside colliery rail-way was, in fact, widely adopted; though it underwent many improvements long before there was any suggestion of operating the new form of traction by means of locomotives.
The first improvement on the original wooden rail pegged on to the sleepers was the fastening on it of another rail, in order that this could be removed, when worn down, without interfering with the sleepers. This arrangement was known as the "double way"; and Nicholas Wood says of it: "The double rail, by increasing the height of the surface whereon the carriage travelled, allowed the inside of the road to be filled up with ashes or stone to the under side of the upper rail, and consequently above the level of the sleepers, which thus secured them from the action of the feet of the horses." He adds that on the first introduction of the double way the under rail was of oak, and afterwards of fir, mostly six feet long, and reaching across three sleepers, and was about five inches broad on the surface by four or five inches in depth. The upper rail was of the same dimensions and almost always made of beech or plane tree.
The next improvement was the nailing of thin strips, or "plates," of wrought iron on to the double rail wherever there was a steep descent or a considerable curve, thus diminishing the friction. These "plates" were about two inches wide and half an inch thick, and they were fastened on to the wooden rails with ordinary nails. They constituted the first step towards the conversion of wooden rail-ways into an iron road, and Nicholas Wood thinks it very likely that the diminution of friction resulting from their use may have suggested the substitution of iron rails for wooden ones.
Cast-iron rails began to come into use about 1767. Their brittleness was, at first, found to be a great disadvantage; but this defect was subsequently overcome, to a certain extent, by the use of smaller waggons, which allowed of a better distribution of weight over the rail. Then in or about 1776 "plates" or "rails" (the two expressions seem to have been used somewhat indiscriminately) were cast with an inner flange, from two to three inches high, so that waggons with ordinary wheels could be taken upon them and be kept on the plate, or rail, by means of this flange.
John Curr, manager of the Duke of Norfolk's collieries, near Sheffield, who claimed to have invented these flanged "plates," describes them in his "Coal Viewer and Engine Builder's Practical Companion" (1797), as being six feet long, three inches broad, half an inch thick, from 47 lbs. to 50 lbs. in weight, and provided with nail holes for fastening them direct on to oak sleepers. Lines so constructed became known as "plate-ways," "tram-ways," or, alternatively, "dram-ways."
The derivation of the words tram and tramway has given rise to a certain amount of discussion from time to time, and the fallacy that they come from the name of Benjamin Outram, of the Ripley iron-works, Derbyshire, who, in the last quarter of the eighteenth century, advocated the flanged-plate system of rail-way, has been especially favoured. It was, however, merely a coincidence that "tram" formed part of his name, and this popular theory here in question is quite unfounded.