MEANS OF COMMUNICATION. 23 
When two tracks diverge at a considerable angle where there is no room 
for curves, as at the stations, horizontal disks of wood or iron, called turn- 
tables, which revolve about a centre, are employed to transfer cars from one 
track to the other. The turn-table is crossed by rails on which, when in 
line with one of the tracks, the carriage is drawn; the table is then revolved 
until the rails are in line with the other track, when the carriage can be 
moved on. Turn-tables are also used to reverse the position of the loco- 
motive on the track. 
The upper part of pl. 3, jig. 4, shows the top view, the lower part the 
substructure ; jig. 5 a section of a turn-table of wrought and cast iron, which 
is in very general use. It revolves about the centre pin, a, on eight cast- 
iron rollers, B, B, ten inches in diameter, carried by the rods, c, c, which 
centre in a wrought-iron ring, p, that turns about the centre pin. The 
bearings of the rollers and of the centre pin are plainly seen in fig. 5. The 
whole is inclosed by a cast-iron ring, =, cast in four pieces. The disk 
consists of four arms, I, 1, crossing it at right angles, and four others, x, x, 
which radiate from the centre; the spaces between the arms are filled with 
an iron grating. On the top of the table are two tracks crossing each 
other at right angles, and corresponding exactly with the track of the road 
in gauge and level. Turn-tables of this construction have generally not 
more than 16 feet diameter. A turn-table calculated to receive a loco- 
motive and tender of 30 feet in length is represented in pl. 3, jig. 1, as 
seen from below; jig. 2 is a cross-section on the line 4’, 3’; jig. 3 a longi- 
tudinal section on a, 8. It revolves in a circular well, and consists only of 
a zone just wide enough to receive the track, in order to be as light as 
possible ; it is readily moved by two men when loaded with the engine and 
tender. . 
c. Stations. The arrangement and size of the buildings at railroad 
stations depend of course on the amount of travel and transportation at each 
station. Stations of importance have,besides the hall for the arrival and 
departure of the cars, a ticket-office, a sitting-room for passengers, a restau- 
rant, baggage-room, &c.; warehouses for goods, locomotive and car houses 
also belong to main stations, together with offices for the transaction of the 
business of the road. On pl. 3, jig. 30, is a view of the Leipsic station of 
the Saxon and Bavarian railroad. 
At suitable distances along a line of railroad are water-stations for the supply 
of the tender. The water is contained in an elevated reservoir from which 
it is carried to the tender by a pipe. /%g.6 shows a water-pipe of improved 
construction ; the pipe 6 issues from the reservoir, and is closed by the stop- 
cock p; when this is opened the water rises in the column a to the valve u, 
which is closed by the weight 6, and opened by means of the lever d, when 
the tender is brought under the supply-pipe r, which can be turned in all 
directions on the support B, E, having a water-tight joint at «. Fig.6 @ 
is a section on the line 3, 4; jig. 7 one on 1, 2, and fig. 8 one on 5, 6. 
Arrangements for warming the water in the reservoir in winter are neces- 
sary in cold climates. 
3. Mortrve Powrr on Ramways. The power by which loads are trans- 
: 603 
