5'2 



NA TURE 



[September 24, 1896 



Combinatinn steain and electric locomotives, gazoline, com- 

 pressed air, and hot-water motors are all being tried in the United 

 States, but definitive results are not yet published. 



The first electric locomotive practically applieil to hauling 

 heavy trains was put into service on the Baltimore and Ohio 

 Railway in 1895 to conduct the trafiic through the Belt Line 

 Tunnel. 



It is stated that, not only was the guaranteed speed of 30 miles 

 per hour attained, but, with the locomotive running light, it 

 reached double that speed. 



On the gradient of 8 per cent, a composite train of forty-four 

 cars, loaded with coal and lumber, and three ordinary locomo- 

 tives — weighing altogether over 1800 tons — was started easily 

 and gradually to a speed of 12 miles an hour without slipping a 

 wheel. The voltage was 625. The current recorded, was at 

 starting, about 2200 amperes, and, when the train was up to 

 speed, it settled down to about 1800 amperes. The drawbar 

 pull was about 63,000 lbs. 



The actual working expense of this locomotive is stated to be 

 about the same as for an ordinary goods locomotive — viz. 23 

 cents per engine mile. 



The rapid extension of tunnel construction for railway 

 purposes, both in towns and elsewhere, is one of the remarkable 

 features of the period under review, and has been greatly assisted 

 by the use of shields, with and without compressed air. This 

 l>rings into considerable importance the question of mechanical 

 ventilation. Amongst English tunnels, ventilation by fan has 

 been a]5]5lied to those under the Severn and the Mersey. The 

 machinery for the latter is, probably, the most complete and 

 most scientific apjilication up to the present time. 



There are five ventilating fans, two of which are 40 feet in 

 diameter, and 12 feet wide on the blades ; two of 30 feet, and 

 10 feet wide ; and one quick-running fan of 16 feet in diameter, 

 all of which were ably installed by Messrs. Walker Brothers of 

 Wigan. They are arranged, when in full work, to throw 

 800,000 cubic feet of air per minute, and to empty the tunnel 

 between Woodside and St. James's Street in eight minutes ; but, 

 unfortunately, it is found necessary, for financial reasons, not to 

 work the machinery to its full capacity. 



The intended extension of electrical underground railways 

 will render it necessary for those still employing steam traction 

 either to ventilate by machinery or to substitute electro-motive 

 force. 



Great improvements have been lately made in the details of 

 mechanical ventilators, especially by the introduction of anti- 

 vibration shutters, and the driving by belts or ropes instead of 

 direct from the engine. The duties now usually required for 

 mining purposes are about 300,000 cubic feet of air per minute 

 with a water-gauge of about 4 inches ; but one installation is in 

 hand for 500,000 cubic feet of air per minute, with a water-gauge 

 of 6 inches. Water-gauge up to 10 inches can now be obtained 

 with fans of 15 feet diameter only. 



An interesting installation has been made at the Pracchia 

 Tunnel on the Florence and Bologna Railway. 



The length of the tunnel is 1900 metres, or about 2060 yards ; 

 it is for a single line, and is on a gradient of i in 40. When 

 the wind was blowing in at the lower end, the steam and smoke 

 of an ascending train travelled concurrently with the train, thus 

 producing a state of affairs almost unimaginable except to those 

 engaged in working the traffic. 



Owing to the height of the Apennines above the tunnel, 

 ventilating shafts are impracticable ; but it occurred to Signor 

 Saccardo that, by blowing air by means of a fan into the mouth 

 I f the tunnel, through the annular space which exists between 

 the inside of the tunnel arch and the outside of the traffic gauge, 

 a sufficient current might be produced to greatly ameliorate the 

 state of things. 



The results have been most satisfactory, the tunnel, which 

 was formerly almost dangerous, under certain conditions of 

 weather, being now kept cool and fresh, with but a small ex- 

 penditure of power. 



In an age when, fortunately, more attention is paid than 

 formerly to the well-being of the men, the precautions necessary 

 to be observed in driving long tunnels, and especially in the use 

 of compressed air, are receiving the consideration of engineers. 

 In the case of the intended Simplon Tunnel, which will pierce 

 the Alps at a point requiring a length of no less than 12^ miles, 

 a foreign commission of engineers was entrusted by the Federal 

 < lovernment of Switzerland with an investigation of this amongst 

 other questions. 



NO. 1404, VOL. 54] 



During the construction of the St. Gothard Tunnel, which is- 

 about ten miles in length, the difticulties encountered were, of 

 necessity, very great ; the question of ventilation was not fully 

 understood, nor was sanitary science sulficiently advanced to- 

 induce those engaged in the work to give it much attention. 

 The results were lamentable, upwards of 600 men having lost 

 their lives, chiefly from an insidious internal malady not then, 

 understood. But the great financial .success of this international 

 tunnel has been so marked as to justify the proposed construction 

 of a still longer tunnel under the Simplon. 



The arrangements which are to be adopted for securing ihe 

 health of the employe's are admirable, and will surely not only 

 result in reducing the death-rate to a minimum, but also tend 

 to shorten the time necessary for the execution of the undertaking 

 to one-half. 



The quantity of air to be forced into the workings will be 

 twenty times greater than in previous works. Special arrange- 

 ments are devised for reducing the temperature of the air by 

 many degrees, suitable houses are to be jirovided for the men. 

 with excellent arrangements for enabling them to change their 

 mining clothes, wet with the water of the tunnel, before coming; 

 in contact with the Alpine cold ; every man will have a bath on 

 leaving; his wet clothes will be taken care of by a custodian, 

 and dried ready for his return to work ; suitable meals of whole- 

 some food will be provided, and he will be compelled to rest for 

 half-an hour on emerging from the tunnel, in jileasant rooms 

 furnished with books and papers. This may ajipear to some as 

 excessive care ; but kind and humane treatment of men results, 

 not only in benefit to them, but also in substantial gain to those 

 employing them, and the endeavour of our own authorities, ami 

 of Parliament, to secure for our own workpeo|ile the necessary 

 protection for their lives and limbs in carrying out hazardous 

 trades and employments, is worthy of admiration. 



The great improvements in sub-acpieous tunnelling can be 

 clearly recognised from the fact that the Thames Tunnel cost 

 1150/. per lineal yard, whilst the Blackwall Tunnel, consisting 

 of iron lined with concrete, and of twenty-five feet internal 

 diameter, has, by means of Greathead's shield and grouting 

 machine, been driven from shaft to shaft a distance of 754 yards 

 for 375/. per yard. 



Tunnels have now been successfully constructed through the 

 most difficult strata, such as water-bearing silt, sand, and gravel, 

 and, by the use of grouting under pressure, subsidence can almost 

 entirely be avoided, thu5 rendering the piercing of the substrata 

 of towns, imderneath ]:)roperty without damaging it, a simple 

 operation ; and opening up to practical consideration many most 

 important lines of communication hitherto considered out of the 

 question. 



On the other hand, very little improvement has taken place in 

 the mode of constructing tunnels in ordinary ground, since the 

 early days of railways. The engineers and contractors of those 

 days adopted systems of timbering and construction which have 

 not been surpassed. The modern engineer is, however, greatly 

 assisted by the possibility of u.sing Brindle bricks of great strength 

 to resist pressure, combined with quick-setting Portland cement„ 

 by the great improvements which have taken place in puinping 

 machinery, and by the use of the electric light during construction. 



A question which is forcing itself upon the somewhat unwilling 

 attenticm of our great railway companies, in consequence of the 

 continual great increase of the population of our cities, is the 

 pressing necessity for a substantial increase in the size of the 

 terminal stations in the great centres of population. 



Many of our large terminal stations are not of sufficient 

 capacity to be worked |iroperly, either with regard to the welfare 

 of the staff, or to the convenience of the tiavelling public. 



Speak to station-masters and inspectors on iluty, when the 

 holiday season is on, and they will tell you of the great physical 

 strain that is produced upon them anil tlieir subordinates, in 

 endeavouring to cope with the difficulty. 



This, if nothing else, is a justification for the enterprise of the 

 Manchester, Sheffield and Lincolnshire Railway Company in 

 providing an entirely new terminus for London. 



It is thirty years since the last, that of St. Pancras, was added, 

 and during that period the population of London has increased 

 by no less than two millions. 



The di-scussion, both in and out of Parliament, of the proposals 

 for light railways has developed a considerable amount of interest 

 in the question. Experience only can prove whether they will 

 fulfil the popular expectations. If the intended branch lines are 

 to be of the standard gauge, with such gradients, and curves as 



