1 84 RAILWAY CONSTRUCTION, 



quantity of suitable material to be placed over the sleepers to 

 protect them from wear by the horses' feet. It can be easily 

 understood that a wooden tramway could not be very durable. 

 It would be affected by the sun, rain, and snow, and particles 

 of sand and gravel thrown on to the tram beams from the 

 hauling path would hasten the abrading or wearing away of 

 the soft portions of the timber into hollows, leaving the hard 

 knots standing out as projections. The uneven surface would 

 produce a series of blows every time a loaded truck passed 

 along, loosening the pieces and rendering the repairs constant 

 and expensive. To obviate the rapid wear of the tram-timbers 

 continuous narrow bars of wrought-iron were fastened on to 

 the running-surfaces; these in a measure prolonged the life of 

 the timbers, but at the same time added to the number of the 

 pieces and fastenings to be maintained. 



Primitive as this description of road appears to be, it was 

 in use for many years in some parts of the United States of 

 America, and even after the introduction of the early locomo- 

 tives; timber was abundant and cheap, and iron in any form 

 was costly. These long thin strips of iron, placed as in Fig. 232, 

 had a tendency to become unfastened at the ends, and to curl 

 up in a very alarming manner, which earned for them the 

 soubriquet of snake heads. Although iron was only used to 

 a limited extent in the first instance, it was soon found to be a 

 much more suitable material for a tram-path than the best 

 timber. As a next progressive step we find that the tram-plates 

 were made entirely of iron, of full width for the wheel-tyres, 

 and with a guiding flange to keep the wheels on the proper 

 track. In some cases the guiding flanges were placed inside 

 the wheels, as in Figs. 229 and 230, and in others outside, as 

 in Fig. 231. With the former plan a thicker covering of gravel 

 or broken stones could be laid down to protect the sleepers 

 under the horse-path. 



These solid tram-plates were made of cast-iron, that metal 

 being considered the most convenient for manufacture and the 

 least liable to suffer loss from rust and oxidization. Another 

 advantage of the cast-iron was that broken tram-plates could be 

 melted down and recast at a moderate cost. 



Long lengths of these cast-iron plate tramways were laid 

 down in this country and abroad, and short portions of some 

 of them remain in existence even to the present day. They 



