126 



SCIENCE. 



[Vol. II., No. 26. 



LOGGIXG LOCOMOTIVE WITH GEAUED DUIVING-WHEELS. 



.runs beside the wheels. Bevel pinions on 

 this shaft engage bevel wheels on the hubs of 

 the wheels, and, as the shaft is provided with 

 universal and telescopic joints, the whole of 

 the wheels can be driven simultaneously, no 

 matter how sharp the curve over which the 

 engine may be running ; and, owing to the 

 interposition of gearing, comparativelj' small- 

 sized cj'linders are sufficient to enable the 

 engine to haul very heavy loads, and j'et run 

 sufficiently fast for the nature of the work. 



Mr. Shay informs us that nearly a hundred 

 of these engines are at work, some on wooden 

 rails, and that thej' are giving great satisfac- 

 tion. The mode of driving appears to be 

 novel, and, despite some complexity, is free 

 from many of the disadvantages of the Fairlie 



system, which also utihzes the adhesion of 

 radiating axles. 



Messrs. H. K. Porter & Co. of Pittsburgh, 

 Penn., also exhibit an engine speciallj' adapted 

 for logging railways. Ordinary metliods of 

 construction are, however, followed ; and the 

 consequent greater simplicitj^ is of great ad- 

 vantage where the work for a few months in 

 the j'ear is very severe, and no repair-shops 

 are situated within convenient distance. The 

 engine exhibited is of the following dimen- 

 sions, and is calculated to work safely on a 

 rail weighing onlj' thirty pounds per yard : — 



Cylinders, diameter and stroke . 10 in. X 16 in. 



Driving-wheels, diameter 36 in. 



Truck-wheels, diameter 22 in. 



Rigid wheel, base 5 ft. 3 in. 



Logging locomotive exhibited bt H. K. Porter & Co. 



