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36 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide
The audio frequency track-circuits provide both train detection and transmission signal aspects.
The vehicle borne equipment reads the code and interacts with the train control system to alert the
operator and/or reduce train speed as necessary. There is ample domestic light rail experience,
and the system can be designed to comply with federal regulations. The cost is likely lower than
power frequency cab signal systems, but thus far has not been applied in the U.S. mainline rail-
road environment. Table 5 provides an overview of the capability of train control systems in
hierarchical order, lists primary components, and notes the extent of safety hazard protection
each affords. Appendix 4 provides relative cost comparisons of various train control systems
for planning purposes.
Command and Control: Communications
1) Communications--Information Processing
Railroad communication systems allow operating personnel to capture operational and
other essential status information; transmit it to various locations, devices or persons that
require this information; enable the systems to process or users to view the various condi-
tions; and issue commands to control, alter or otherwise acknowledge the status. The con-
stituent pieces that effect this capture and transmission of information and serve both verbal
and data content include:
· Command & control information--voice, data (i.e., the information content to be monitored
or transmitted);
· Carrier technology--medium of transmission via wire, wireless radio, fiber optic, land line or
cell phone;
· Carrier frequency--VHF, UHF, SHF, spread spectrum (i.e., the format of the data transmitted);
· Communication system components--hard wired or portable radio, landline or cell phone,
CRT display, mimic board, data transmitters/receivers, compatibly linked via interface devices
to the transmission and frequency carriers.
2) Regulatory and Practical Requirements
For shared-track operations, an entirely new communications system will be required for
the passenger service, and must, by regulation, incorporate direct interconnection with the
freight carrier. On a shared-track system, the transit control center should be the exclusive hub
for all freight and transit communications related to safety and train movement. The system
component design and functionality must be based on a combination of published standards
and regulations.
· Onboard equipment has to comply with the APTA Manual of Standards and Recommended
Practices, for Rail Passenger Equipment, Volume VI, Standard for Passenger Railroad Emergency
Communications and American Railway Engineering and Maintenance of Way Association
(AREMA) Communications & Signal Manual of Recommended Practices Volume V, 2006. This
contains railroad frequency and channel information for radio transmission systems.
· FCC requirements. Operator needs to apply for license for base stations (antenna height,
broadcast range, and frequency license for transmission) for all wireless communications
networks.
· FRA requirements. Operator must comply with relevant FRA regulations for railroad com-
munication. The FRA regulations and policies for shared-track operations appear in the Code
of Federal Regulations (CFR), in 49 CFR Parts 209 and 211. Other Federal Regulations includ-
ing 49 CFR Parts 217, 218, and 220 also influence the control of rail operations. Requirements
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Table 5. Overviews of capacity of train control systems.
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