The problem involved the prime consideration of:
Safety and reliability.
Greatest capacity of the lines consistent with the above.
Facility of operation under necessarily restricted yard and
track conditions.
In order to obtain the above desiderata it was decided to install a
complete automatic block signal system for the high-speed routes,
block protection for all obscure points on the low-speed routes, and
to operate all switches both for line movements and in yards by power
from central points. This necessarily involved the interconnection of
the block and switch movements at many locations and made the adoption
of the most flexible and compact appliances essential.
Of the various signal systems in use it was found that the one
promising entirely satisfactory results was the electro-pneumatic
block and interlocking system, by which power in any quantity could be
readily conducted in small pipes any distance and utilized in compact
apparatus in the most restricted spaces. The movements could be made
with the greatest promptness and certainty and interconnected for the
most complicated situations for safety. Moreover, all essential
details of the system had been worked out in years of practical
operation on important trunk lines of railway, so that its reliability
and efficiency were beyond question.
The application of such a system to the New York subway involved an
elaboration of detail not before attempted upon a railway line of
similar length, and the contract for its installation is believed to
be the largest single order ever given to a signal manufacturing
company.
Pages:
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171