Page:The Canal System of England.djvu/58

 system— an electric motor running along a track on the towing path—supplied with current from overhead wires, on the trolley system. One man is required to drive the motor, and the barge, which is merely connected by a towrope with the motor would have the usual two hands aboard. The estimated cost of haulage ranges from 9d. to 12d. per barge mile and the speed would be from 2 to 3 miles per hour.

Should the experiments be carried out and be found to facilitate navigation and cheapen transport to the extent anticipated, this system will doubtless be introduced on most of the canals of this country, as the aggregate saving on the volume of canal traffic would be very large.

The Thwaite-Cawley is another form of electric haulage. In this system an aerial railway is provided at an elevation of 9 ft. or 10 ft. above the towing path, supported by cast-iron or wooden posts placed at 30 ft. intervals. Along this elevated track run a number of four-wheeled electric motors, with two of the wheels on the upper and two on the lower surface of the rail, the axles being proportioned so as to regulate the pressure of the wheels upon the track. The tow-rope is attached to a link at the back of each motor.

Two rails are provided forming an "up" and a "down" line, so that when two barges are passing in opposite directions the one connected with the motor on the upper rail steers wide and its tow-rope passing clear over the first, no stoppage is necessary.