88 Book of Engineering 



gear, quite a simple operation and one which 

 has been proved to be efficient. 



It is a wonderful achievement really to 

 have produced a tug which is equally at 

 home on land or water, and it is remark- 

 able to see her leave the water, ascend 

 gradually the inclined mono-rail, travel 

 along the level for a short distance, 

 and then head for the second channel 

 with her train of barges behind her. In 

 order that these shall not over-run their 

 mentor on the descent to the water 

 again, a set of powerful shoe brakes is 

 supplied for the wheels. These, by the 

 way, consist of four sets of two wheels 

 in line. 



The two hulls are quite distinct as units, 

 and are steel-built. They are joined by a 

 platform, under which are the wheels 

 referred to. The platform is laid upon 

 transverse girders, and it serves as a con- 

 necting link between the train and also as 

 the bridge of the craft. The total beam of 

 the double-hulled barge is 18 feet, and when 

 rail-borne they maintain their equilibrium, 



