and a private line may be brought into the middle one. When the
next block rings up, a visual signal is displayed which operates a bell
in the office by means of a local circuit. The operator answers by
plugging the telephone cord extending from the bottom of the set into
the proper jack. This automatically restores the signal and stops the
bell.

[Illustration: Fig. 499. Blocking Set]

Below these signals appear four jacks. One is wired across the train
wire; one across the message wire; and the other two are bridged across
the two pairs of patching cords on each side of the set. The operator
answers a call on any circuit by plugging his telephone cord into the
proper jack.

If a waystation is not kept open in the evening, or the operator leaves
it for any reason and locks up, he can connect two blocks together by
means of the block-wire cords. These are arranged simply for connecting
two grounded circuits together and serve to join two adjacent blocks,
thereby eliminating one station. A jack is wired across these cords, so
that the waystation operator can listen in on the connection if he so
desires.

In some cases not only are the telephone circuits brought into the test
board, but also two telegraph wires are looped through this board before
going to the peg switchboard. This is becoming quite a frequent practice
and, in times of great emergency, enables patches to be made to the
telegraph wires as well as to the telephone wires.

=Dispatching on Electric Railways.= As interurban electric railways are
becoming more extended, and as their traffic is becoming heavier, they
approximate more closely to steam methods of operation. It is not
unusual for an electric railway to dispatch its cars exactly as in the
case of a steam road. There is a tendency, however, in this class of
work, toward slightly different methods, and these will be briefly
outlined.

On those electric railways where the traffic is not especially heavy, an
ordinary magneto telephone line is frequently employed with standard
magneto instruments. In some cases the telephone sets are placed in
waiting rooms or booths along the line of the road. In other cases it is
not feasible to locate the telephone indoors and then iron weather-proof
sets, such as are shown in Figs. 484 and 485, are mounted directly on
the poles along the line of railway. With a line of this character there
is usually some central point from which orders are issued and the
tra