30 POWER DISTRIBUTION FOR ELECTRIC RAILROADS.
The figures just given emphasize with tremendous force
the need of thorough bonding of the track in order to take
advantage of its immense conductivity. In the early elec-
tric railways this was terribly neglected, the bond wires
sometimes being as small as No. 6 and even of galvanized
iron. Bonding is of very various character. Its most
rudimentary form is shown in Fig. 18. In this case the
1,500,000
1,000,000
Circular Mills
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treet Railway Journal
FIG. I7.
bonds merely united the ends of adjacent rails, each line of
rails being bonded separately. ‘The improvement of Fig.
19 is quite obvious, for in Fig., 18 a single break compelled
one rail to carry the return load. The cross bonding of
Fig. 19 adds somewhat to the weight of copper required,
but ties the rails together so that no single break can be
serious and nothing save a break from both rails on the
same side of the same joint can really interrupt the circuit.
A very large amount of track has been so bonded, al-
though at present the usual construction is shown in Fig.