MECHANICS AND USEFUL ARTS. 55 



the Cromfovd and High Peak Railway for experimental purposes, 

 in 1863, that tlie system Avas put into practical operation, the 

 experiments being entered into in order to satisiy the Italian Gov- 

 ernment as to the feasibility of laying down a line on a similar 

 principle over one of the Alpine passes. The mean gradient of 

 the first twenty-four miles of line, from St. Michael to Lausleburg, 

 is one in sixt3', Avith a maximum gi-adient of one in twelve ; the 

 other twenty-four miles, the mean is one in seventeen ; and over 

 the whole length there are at intervals curves of two chains radius. 

 The line rises to an elevation of seven thousand feet, and is ex- 

 posed in places to avalanches and heavy snow-drifts ; but it will be 

 suitably protected. The system of locomotion adopted was that 

 of a third or traction rail, on which adhesion could be obtained by 

 horizontal wheels, worked by the engine in conjunction with or 

 independently of the ordinary driving-wheels, which admitted of 

 the weight of the engine being reduced to a minimum, while the 

 pressure upon the middle rail could be carried to any required 

 amount, and gradients of one in twelve worked with as much 

 certainty and safety as those of one in a hundred. The centre- 

 rail also furnishes the means of applying most powerful brakes 

 for controlling the descent of the trains, and greatly diminishes the 

 frictional resistance in passing round sharp curves. Besides this, 

 the centre-rail rendered it almost impossible for the train to leave 

 the rails. The first experiments were tried in the Cromford and 

 High Peak Railway from September, 1863, to February, 1864. 

 The weight of the engine and load was from sixteen to seventeen 

 tons. It never failed to take loads of from sixteen to twenty-four 

 tons up gradients of one in twelve, or in working round curves 

 of two and a half chains radius on that incline, the brakes having 

 perfect control over the train on the ascent. Certain improve- 

 ments suggested themselves, — the boiler-power was insufficient, 

 the inner machinery too crowded and inaccessible, and the con- 

 necting-rods, working at too great an angle, by an irregular, 

 impulsive movement, diminished the adhesion of the horizontal 

 wheels. The improvements were made and further experiments 

 conducted with special reference to the requirements of the Italian 

 Government, which included three trains a day each way, the mail 

 train to perform the joui'ney at an average rate of twelve miles 

 ah hour, including stoppages, the speed up the steepest incline 

 being seven and a half miles an hour, while the gross weight of 

 the train was to be sixteen tons. The mixed and goods trains 

 were to carry forty and forty-eight tons each, with two engines. 

 The traffic on these trains represented a return of £100,000 an- 

 nually. The writer described the official trials in Italy in the 

 presence of the representatives of the English, Italian, Russian, 

 and Austrian Governments. The I'esult of the trials exceeded the 

 estimate both as to speed and weight of the trains, and Captain 

 Tyler, who represented the Board of Trade, reported "that this 

 scheme for crossing the Mont Cenis is, in my opinion, practica- 

 ble, both mechanically and commercially, and that the passage of 

 the mountain may thus be elfected, not only with greater speed, 

 certaint}% and convenience, but also with greater safety, under 



