AN ELECTRIC RAILWAY.

Globe, Volume XXI, Issue 1790, 15 November 1879, Page 4

AN ELECTRIC RAILWAY.

Respecting the electric railway which has been in operation at the Berlin Industrial Exhibition some particulars are given in the “Archiv fur Post und Telegraphic,” from which we learn that this new exemplification of the application of electricity as a motivepower sprang from a question addressed by Herr W eatphal, a master builder of Cottbus, near Berlin, as to the possibility of utilising the'foroe generated by coal burnt at that village hy transmitting it to Berlin. The gentleman in question bad road a remark respecting the feasibility of transmitting the forco of the Niagara Palls to a distance, and he wished to attempt to carry out practically a similar application at Homo. The problem ultimately resolved itself into the question how far electric forco could bo as a motive-power on rails. The experiments which were instituted were crowned with success, and led to the construction“of the electric railway as it has been seen in operation in the Berlin Exhibition. The arrangement is as follows :—There are two lines of rails laid down, which, as in anarrow gauge line, return into themselves in a ring-shaped curve. The length is about 300 metres, _ln the middle is an isolated third line, cor sisting of an upright, continuous iron plate. The locomotive carries two rollers, with which it stands in connection with tho isolated middle lino. The essential portion of the locomotive is formed by an electro-dynamical machine, one pole of which is connected with tho middle line and the other with the pair of outer rails, through the outer wheels. Similarly the machine which produces the current stands in the machine room in connection through one pole with the middle line and through tho other pole with tho outer pair of rails. When, therefore, the dynamical machine in the locomotive is on the railway, the electric current produced in the machine soon runs through it and causes it to rotate and to impart its rotatory motion to the wheels c£ tho locomotive, and tho latter continues to move until the current is interrupted. Even an imperfect state of isolation on tho part of tho rails does not materially affect tho action of the machine. When the locomotive is moving its conducting wires form much better conductors than the damp earth. If tho current is interrupted, the damp ground is not a sufficient conductor to keep the dynamo-electrical action going. The magnetism of the machines producing the current consequently disappears, and tho result is that tho subordinate stream through the earth is also interrupted. A great advantage is possessed by the transmission o c electric force from tho fact that the locomotive whether moving slowly or quickly, always works up to its full power—an effect which has hitherto been an unsolved problem in mechanics. When tho machine that gives the power has to do much work and bo goes Blowly, the counter currents it produces arc also correspondingly weak, and tho current through the conductors thereby undergoes an increase in strength to a similar extent. By this moans the electro-magnetism and, corresponding to this, the attractive power of tho machine are increased. The dynamo-electric locomotive has the further advantage that it carries in itself tho power which can bo employed na a brake, inasmuch as it becomes iteclf tho primary or current producing machine when it rotates more rapidly than tho actual machine. In judging of the performances of the electric locomotive in tho Berlin Exhibition it must bo remembered that it was not constructed for tho purpose to which it has been applied —that is, to propel tho three elegant lilt'o passenger carriages which are attached to it. Each carriage holds from eighteen to twenty persons, and all three tiro drawn in from one to two minutes round tho circular railway of 300 metres in length. Tho locomotive was originally made for tho purpose ot drawing up coals out of tho pit. Nevertheless, its performances arc very remarkable, and render it certain that there are many cases in which electric locomotives may bo employed with advantage. Tho question of the extent to which electro-dynamic locomotives 'may possibly be employed is us] yet difficult to decide. Apart from tho question of the possibility of a sufficient isolation, it depends on the conductive resistance of tho rails. According to Dr. Siemens’ view, this requisite on long railways may bo partly satisfied by setting up from time to time now primary dynamo-olectric machines, which would maintain tho necessary electric tension between the middle and the outer rails.