314 THE COLLIERY GUARDIAN. February 18, 1916. scams 20 in. thick, or even 18 in. thick. There were other adverse factors which operated in Great Britain, such as stringent Acts of Parliament, trades unionism, old customs, restrictions on employment of both young and old, short hours of labour, too many holidays, includ- ing the fortnightly pay Saturday; in fact, the restric- tions were almost innumerable, and many of them were practically insurmountable. He submitted a table showing that the output of coal per annum per man was steadily decreasing in the United Kingdom, and had fallen 17 per cent, between 1886 and 1911; in America, the output had increased by 65 per cent, from 1886 to 1912; and that of Australia, New Zealand, and Canada had gone up 63, 40, and' 38 per cent., respectively. Naturally, a restricted supply enhanced prices, so that whilst the output per person employed had lessened, the price or value per ton at the pit mouth had increased. There was probably the same margin of profit at the best collieries, where the labour cost bore a smaller pro- portion to the total cost, but that was not the case at those collieries where thin., hard, and difficult seams were being worked. The reduced output at these latter collieries had, in many instances, resulted in the stoppage of the pit. The high cost of coal on the manu- facturing trade had a baneful and far-reaching effect, and it probably accounted for the slow advancement in iron production, which had been' practically stagnant for many years. Whereas, in 1865, Great Britain made five times as much iron as Germany, the latter country had passed us in 1910, and made 50 per cent, more than we did. In the production of steel, we were still further behind, and, in 1910, Germany produced nearly twice as much as this country. There were, he thought, three principal causes for the backwardness. First, the coal owner had often been too conservative in his ideas of .business, too indifferent to the changes which had been gradually taking place in the labour world, and also to his dual interests in the working man’s labour and vote. Secondly, politicians of both parties desiring to obtain votes had increasingly flattered both masters and men and, instead of prevent- ing the workers from reducing their output to a minimum, had actually encouraged them in that suicidal policy by restrictive legislation. The politicians had encouraged idling on the part of workmen, and the result was that this country had fallen, much more rapidly than she ought to have done, from her position as the premier coal producing country, to a secondary position. Thirdly, there was the restrictive policy of the trades unions, which had nullified the benefits expected from the great improvement in mining machinery in the way of increasing the output and reducing the more laborious part of coal mining. The result was that British coal miners had succeeded in reducing the output per man and in creating an artificial scarcity with spuriously augmented prices. This must have a detrimental effect on our industries, and would some day result in a reduced demand for both our manu- factured goods and for our coal and iron. The great difference in the methods practised in America and in Great Britain seemed to be that, in America, the wages paid were in proportion to the output, whilst in this country they were in proportion to the selling price, the result being that in America every effort was put forward to obtain a big output cheaply, whilst here enhanced wages had to be paid because of restricted supply. In other words, the harder the American miner worked, the higher were his wages, whilst here the smaller the output was the higher were the wages. Mr. Samuel Hare (Bishop Auckland) said there was one thing Mr. Tate had said that should not go uncriticised, namely, that the labour-saving machines, especially the coal cutters, in America were responsible for the larger output per man, and that English mining engineers had done as much as the Americans in that respect. Personally, the speaker did not agree with that. For some years now, he had been watching American mining. He had tried American machines, the very latest machines, and the best American operator. The man, however, could not do any better than any of their own men could, and the machine itself could not do any better- than they were doing at the colliery before it arrived. So far as longwall working was con- cerned, he thought that most of them would agree that English longwall machines were as good as the American machines. He had used both kinds, and thought that ours were just as good? Goal-cutting machines for bord- and-pillar working were an entirely different proposition. There was an enormous difference in American condi- tions in which those machines were employed and the conditions under which our .machines had to work. The illustrations to Mr. Dean’s paper showed that there was hardly a stick of timber in very large working places, whereas our places had to be timbered very often close to the face, and it was practically impossible to get those big bord-and-pillar machines to work in an ordinary English pit. Then there was the question of depth. He could not imagine any pits of the average depth of English pits being worked with the shortness of timber with which they seemed to work in America. He assumed that, in very many cases, the coal cutting was done at very limited depths. He had 'tried the very heavy rails, of which Mr. Dean spoke, up to 601b. per yard, in order to get these machines quickly transferred, from place to place and—American operators were employed—it was very difficult, unless they were able to use naked wires, which was absolutely contrary to the Coal Mines Acts. The conditions were so very different .in the two countries that no comparison could bo made, but if we had in England anything like the conditions that obtained in America, our mining engineers were quite equal to those in America, and could obtain equally good results. With most of Mr. Tate’s other remarks he was in absolute accord. (To be continued.) THE LOGIC OF TRAMS * By John Gibson. While appliances for winding, pumping, hauling, ventilation, and other purposes have been exhaustively treated, the tram or tub has been much neglected. Collieries may exist without pumps, mechanical haulage, or winding engines, but all possess one article in common—the tram. It is the appliance with which the workmen are brought most closely into contact. Perhaps on account of this it enjoys the most varied nomenclature, “ wagon,” ” box,” “ tram,” “ tub, “ hutch,” “ whirley,” “ corve,” and “ car,” being some of the many names given to it. No scheme has been applied in planning it; and no co-ordinated thought has been devoted to its construction. In one colliery a 2-ton tram may be used, while under not dissimilar con- ditions a 4-cwt. tram may be employed in another. In one colliery a 14-in. gauge may be used, and in another a 42-in. gauge. Neither in the size of the tram nor in the width of the gauge can such differences be recon- ciled with reason. The differences are the result of haphazard, design and want of thought. The writer hopes to prove that the economical tram is of even greater importance than, say, the economical engine, and as no difficult and involved calculations are required, and all the governing facts are simple and well known, the former is more easily attainable than the latter. Many different types of trams and widths of gauges are in use in this country. The waste and expense of such a want of system is appalling. Can it be said that the-conditions are so diversified that all these types are necessary? Is it not easily practicable to reduce the number of types, and to standardise their manufacture, so that they can be turned out in thousands at a minimum cost? Factors Governing the Size of the Tram. If a man were set to move coal a distance of 10 ft., the easiest and cheapest way would be to shovel it. If the distance were 10 yds., a wheelbarrow would be the most convenient article to employ, because easily tipped. If the distance were 100 yds., a side- or end-tipping wagon holding 20 or 30 cwt. would perhaps be best. It follows, then (othbr considerations apart) that the greater the distance is, the larger the wagon should be. This rule is subject to important exceptions, however. If the gradient is more than 1 in 40, a man working single-handed would have great difficulty in pushing or controlling a wagon holding 20 or 30 cwt. It is, there- fore, clear that inclination is an important factor, because in every colliery every tram is more or less man- handled. When the tram is underground, another important factor must be considered—the size of the road. The ordinary haulage roads are usually big enough to take very large trams, but not so the gate roads. In thin seams a pre-determined minimum height and width of gate road is set up by the size of the tram. If this be too large, either repairs of the road are excessive, or new cross gates are frequent. In both cases the size of the tram- governs the dimensions of the road, and is responsible for all unnecessary expense. A man has no great difficulty in travelling in a road having a minimum height of 3 ft. above the rails, and a width of 3 ft. between the narrowest timbers, and the writer suggests that the minimum- or smallest-sized tram should be 2J ft. high and 2| ft. wide. Where the gate road branches ofi the cross gate, the tram must often be turned at right angles, and this is frequently and conveniently done on a turnplate. The width of the road at this point determines the length of the tram, and one 2J ft. wide by 4| ft. in length over all can be turned on a road 6 ft. wide, and sjill allow of some little freedom of movement to the work- man between the tram and the timbers. Such a tram, then, 44 ft. long by 2J ft. in width by 2J ft. in height may be termed the No. 1, or minimum size. Wheels, etc., will be considered later, but if a weight of 3 cwt. be assumed in the meantime, it might now be considered what can be done with this tram. In gate roads it is (and more especially if the roof is tender) cheaper to draw by hand to the limit of inclina- tion, rather than resort to self-acting inclines of any kind, because these require greater width, and conse- quently handling extra debris, heavier timber, thus entailing greater expense. For short distances a well-developed young man can exert a force of 120 lb. The writer has found that a force of 601b. can be usually given through a distance of 110 yds. in 2| minutes without great exhaustion. This is equal to 0-24 horse-power. A lad of 14 to 17 can exert two-thirds of this force, that is, 0-16 horse-power. Assuming the coefficient of friction to be a sixtieth, the man can push an empty tram weighing 3 cwt. up a road rising 1 in 6 for a distance of 110 yds. in 21 minutes. A lad can tackle a gradient of 1 in 9-J. Under unfavour- able conditions, with the tare of the trams high com- pared with the gross load and a high coefficient of fric- tion, a self-acting incline would work on this road. Consider now the relative importance of weight and friction. If the weight were increased from 3 to 4 cwt., the limit of inclination in the road mentioned would be 1 in 8| instead of 1 in 6. With a 3-cwt. tram, if the friction were doubled, the limit of inclination would be 1 in 6'9 instead of 1 in 6. It is clear, then, especially in roads rising towards the faces, that to keep the weight low is of far greater importance than to keep the coefficient of friction low. Where the roads dip towards * From a paper read before the North of England Institute of Mining and Mechanical Engineers. the faces, the case is slightly different. With a loaded tram weighing 10 cwt., the gradients are as follow :— With One Man Behind the Tram. Weight. Friction. Limit of inclination. 10 cwt. ... Aj ... 1 in 49 approximately. 10 „ ... -Jo ... 1 „ 27 With Two Men Behind the Tram. Weight. Friction. Limit of inclination. 10 cwt. ... -Jo ••• 1 in 13 5 approximately. 10 ,, ...- Jo ... 1 ,, 11 ,, Roads dipping to the face are the exception rather than the rule. It is therefore clear that, especially in small trams, the weights must be kept down as low as sound construction permits, even if it involves a certain amount of increased friction. With larger trams the greater height of road permits of the use of ponies. It is assumed that, where the trains are mechanically hauled on main roads, it will be immaterial whether 100 or 150 horse-power be expended if the advantages gained close to the face, where the trams are man- handled, are sufficiently great. It is also clear that, as the weight and the carrying capacity of the tram increase, the importance of friction becomes greater. It follows that wheels of small diameter and simple bearings are suitable for small trains, and that large wheels should be fitted to large trams. When a diameter of 14 or 16 inches is reached, friction may be most suitably reduced by ball or roller bearings and high-class lubricating arrangements. In the case of the small tram referred to, perhaps an 8-in. wheel would be most suitable. The writer has no desire to lay down axioms as to what sizes of standard trams should be adopted, but he puts forward the following proposition as a basis for discussion. Starting with a tram 4| ft. long by 2f ft. wide by 2J ft. high, in each succeeding size, up to 6 ft. over all, the length, breadth, and height would be increased by 3 in., 2 in., and 2 in. respectively. Proposed Scale of Standard Trams. Over-all measurements. Inside measurements. A C15 N *5 rfl rfl 'S rfl bD ■M s ' § ’© cS fl o © *© fl 0) Hl c © 5 Q Ft. in. . Ft. in. Ft. in. Ft. in. Ft. in. Ft. in. . Cwts 1 . ... 4 6 ... 2 9 ... 2 6 ... 3 19 ... 2 7 . ..16 ... 6 2 . ... 4 9 ... 2 11 ... 2 8 ... 4 1 ... 2 9 . ..1 7i.. 7| 3 . ...5 0 ...3 1 ... 2 10 ...4 4 ... 2 11 . ..19 ... 8f 4 . ... 5 3 ... 3 3 ... 3 0 ... 4 7 .. 3 1 . ..19 ... 9f 5 . ..5 6 ... 3 5 ... 3 2 ... 4‘ 9 ... 3 3 . .. 1 10 ... lit 6 . ... 5 9 ...3 7... 3 4 ... 4 11 ... 3 5 . .. 1 11 ... 12f 7 . ..6 0 ... 3 9 ... 3 6 ... 5 2 ... 3 7 .. ..2 0 ... 1H 8* _ ... 6 6 ... 4 0 ... 3 8 ...5 6, ... 3 10 .. .. 2 2 ... 18 9* ... 7 0 ...4 3... 3 10 ... 6 0 ... 4 1 . ..2 4 ... 23 o -4-= d) . In. ... 8 ... 9 ... 10 ... 11 ... 12 ... 13 ... 14 ... 14 ... 14 . *In sizes over 6 ft. over all, the length, breadth, and height would increase 6 in., 3 in., and 2 in. respectively. Note. — The inside measurements and capacities are approximations only, and would vary according to the material used and the method of construction. The above capacities are water measure. It would, of course, be easy, in the event of standards being adopted, to increase or decrease the depth of a tram so as to suit pairticulair conditions. Thus one colliery finds that No. 9 is quite suitable except for the height, which is too great; or another colliery requires No. 3, but could take greater height. It is possible that standard trams would be somewhat unsuitable in some particular cases; but, even then, the advantages would be exceed- ingly great. A short examination of the present conditions will prove that statement. When a colliery is about to be started, the owner may possess from one of his other collieries, wheels, pedestals, underframes, etc., and may decide to use the same or a similar type of 'tram in order to utilise the material and prevent repair and spare parts complications. The tram is almost certain not to be suitable for both the old and the new collieries. If the owner sets up a new type of tram, two classes of spare part have to be stocked and repairing generally becomes more expensive. Not only so, but, if No. 1 colliery urgently requires for a period extra trams, No. 2 colliery cannot render help, because the types are different. Or, again, a colliery is sunk to win a 7-ft. seam and a 2-ft. seam. The same tram cannot suit both. A compromise arrangement may suit neither, and the cost of changing is pro- hibitive. • When a colliery is working, trams have to be bought at first cost; but when the colliery is exhausted, they are of little use to anyone, and are sold at scrap prices. It is not uncommon, therefore, to find that in collieries nearing exhaustion the trams are allowed to get into a state of low efficiency. With a standard tram the value at any period of its life would- be well known. If, therefore, it were found that a particular tram was unsuitable for a certain colliery, another type would be obtained in exchange at a very small cost. Indeed, if the change were from a larger to a smaller type, the coal owner might receive hard cash in addition to new trams. A different type might be used in every seam in the same colliery. The size of the trams affects the cost of getting the coal to the road head. Thus if the tram is large, a man of full physical strength is required, even on easy gradients, to provide for derailments; but, whilst a lad . has two-thirds the strength of a man, he is usually paid only half the wages. Now a drawer is but partly occupied, as waiting takes up more or less of his time. It follows, then, that if a third of a drawer’s time is lost, the loss due to a man at 7s. 6d. per day is 2s. 6d., while that due to a lad at 3s. 9d. is Is. 3d. If, where two men are now employed, the production being 5 tons per day, trams suitable for a lad were adopted, the output for a man and a lad would be five-sixths of 5 tons, or, say 83 cwt. The cost would be Ils. 3d., or approximately 2s. 9d. per ton—a saving of 3d. per ton, or Is. 3d. for 5 tons.