American Audio VELOCITY - REV 4-05 Betriebsanleitung PDF herunterladen (Seite 57)

METRO RAIL DESIGN CRITERIA SECTION 9 / SYSTEMS

DE304.09 9-52 Revision 4 : 05/09/12

Metro Baseline Re-Baseline: 04/29/10

All vital components shall be highly reliable, of proven design and have predictable failure

modes, such that no single failure shall create a less restrictive state.

The signal system logic and its components shall be designed to meet the following:

a) All vital components shall be designed so that restrictive (rather than permissive)

actions occur when a component fails.

b) All vital control logic shall be designed such that, if interrupted or de-energized, it

shall cause the controlled function to assume its most restrictive condition.

c) All relays or solid-state equivalents being energized by a vital circuit shall be

vital units. All contacts used within any vital circuit shall be contacts of vital

relays.

d) All errors of hardware and software that may compromise vital data, whether

stored within a logical process, sampled as digital or analog inputs, or produced

as digital or analog output, shall result in a safe system state.

Non-vital circuits may use non-vital relay or solid-state technology. Failures of non-vital

equipment shall not affect the safety of the system. Non-vital systems shall interface with

vital systems in a manner, which isolates the vital systems from malfunctions of the non-vital

systems.

Vital microprocessor systems shall be used.

The use of radio, land cable, or any combination, which forms a serial communication

channel for the signal system, shall not be considered vital in itself. Design techniques shall

be employed such that the equipment at each end of the communication link shall be

capable of detecting errors in the data transmitted and received, such that system operation

remains safe.

9.4.2.19 Materials and Equipment

9.4.2.19.1 General

Assemblies and components used to perform identical functions within the system shall be

mechanically and electrically interchangeable. Standard commercially available equipment

and material from multiple sources shall be used where practicable.

All wayside equipment shall be secured and protected by the use of tamper-resistant

covers. Where deemed appropriate by the Designer, further protection shall be provided

with intrusion detection devices.

All cables and wires shall be suitably protected. Conduits shall be provided under tracks,

along bridges and through roadways, to meet AREMA recommendations. All material and

equipment furnished shall be new and standard products of manufacturers regularly

engaged in the production of like equipment.

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American Audio VELOCITY - REV 4-05 Betriebsanleitung Seite 57