Improvement in 'Rail Roads, 871 
by this means, the workmen are obliged to form their 
road in right lines, and maintain perfect levels, as the 
mortice and tenon confines them to the required exactness 
necessary to make a perfect road : curves or any given 
segment may be formed with the same nicety, by having 
two bevel rails or plates made for such purposes. 
Fig. 8, A side view or longitudinal section of the two 
plates placed on their stone blocks or sleepers CD, shows 
two plugs in dotted lines, one bevel, the other perpendi- 
cular, cast in the stop-rail or plate, which is so called as it 
prevents the others from moving, and when taken up re- 
leases all those between the stop-plates ; twenty-five yards 
of rail roads made with these plates, may be taken up and 
replaced within ten minutes. The plugs in dotted lines 
are shown in their proper positions within the sleepers 
EFGr. 
The usual length of a tram-plate is three feet, the 
flancli or outside edge H, about one inch and half high, 
the sole or bed I, from three inches and a half to four 
inches broad, and three fourths of an inch thick; but 
these dimensions may be varied according to circum- 
stances. The most approved weight has been fourteen 
pounds to the foot, or forty-two pounds to the plate, the 
ends from which the plugs project, and to which the 
tenons and mortices fasten, should be one fourth of an 
inch thicker than the other part of the plate. 
Fig. 9. AB show the under part of the tenon and 
mortice, and the form of one of the sloping or bevel 
plugs. 
The diameter of the plug near the shoulder is one inch 
and three quarters, reducing to one inch, its length two 
inches and a half, forming an angle of eight degrees, the 
plate from which it projects is counter sunk, so that the 
shoulder of the plug may not receive any sharp pressure 
or prevent the plate from having a perfect bearing. 
