1904.] 071 New Developments in Electric Bail ways. 473 



diminished, the next best being made on the 11th of November, 

 when the periodicity was 45 • 3 per second, the speed of the Allge- 

 meine Elektricitiits Gesellschaft car 196 km., corresjDonding to a siij) 

 of 8*4 per cent., and the speed of the Siemens car 208 km., corre- 

 sponding to a slip of 2 • 8 per cent. 



Again, on the 25th Novumher, with a periodicity of 45} per sec. 

 the Allgemeine Elektricitiits Gesellschaft car attained 204*9 km., a 

 slip of 3*9 per cent., and the Siemens car 207-3 km. per horn*, a slip 

 of 2 j per cent. 



The difference in the slij) of the two motor cars is probably due 

 to the fact that at full speed the Siemens motors are metallically 

 short circuited, while in the circuit of the Allgemeine Elektricitats 

 Gesellschaft motors the liquid resistance is not quite removed. 



I am indebted to the Allgemeine Elektricitats Gesellschaft and 

 to Siemens and Halske for the photographs and the information about 

 last year's trials, which I have been able to place before you 

 to-night. 



In any case, the results of these trials clearly establish the fact 

 that it is possible to run uj) to a speed of 200 km., or 125 statute 

 miles, per hour on the same permanent way as is now used on well- 

 built main lines for express traffic, and that at such a speed the high 

 tension electric current can pass from the stationary conductors along 

 the line to the moving car without difficulty. 



These two facts are quite independent of the kind of motor em- 

 ployed, and are equally applicable to the other railway motors which 

 have been described during the lecture. 



The electrical engineers can claim, therefore, that they are quite 

 ready to run main line traffic by means of electrical motors, and that 

 they are prepared to do so at about double the speed of the present 

 express trains — in fact, that technically, the i3roblem has been solved 

 in a satisfactory manner. 



It would be rash, however, to assume from these successes that 

 steam locomotives will disappear in the near future from the main 

 lines of railways, to be replaced by fast running motor cars, following 

 each other in quick succession. 



No innovation in this material life has any chance of general and 

 permanent introduction, unless in replacing existing means it intro- 

 duces a saving of money. 



Applying this rule to the present case it is at once apparent that 

 the existing main lines, although their permanent way has been 

 proved to be sufficiently strong, do not lend themselves to the 

 immediate use for rapid transit on account of the curves which occur 

 in them. 



As stated before, the worst curve on the Zossen line has a radius 

 of 2000 metres, which is, for ordinary traffic, almost negligible ; but 

 during the rapid transit experiments the speed of the cars had to be 

 lowered to 160-170 km. per hour when passing through these curves, 

 in order to make their running reasonably safe. 



