Download VPI II Overview

Vital Subsystem
VPI II APPLICATION MUST BE FIELD TESTED
Field testing of a VPI II application is required before placing the location into
revenue service. The customer’s testing plan and safety plan define the
testing requirements for the VPI II application.
Failure to comply can degrade the safety performance of the train control
system resulting in property damage, injury, and/or death due to train
collision or derailment.
The application of VPI II depends on application engineers defining configurations and
logic to be implemented for the interlocking application. While VPI II guarantees that
logic and outputs, etc., are managed vitally, there is no intrinsic check on the
correctness or completeness of the signaling logic as it is intended to meet the
requirements of the transit/railroad application. It is a primary safety requirement that
the logic produced for VPI II execution be independently verified as correct and
complete through a “circuit check” type process. The check process must be performed
by engineers knowledgeable in the requirements of the signaling rules that govern
transit/railroad operation and independent from the engineering staff that produced the
logic.
P2511G, Rev. D, Jan/15
5–40
Alstom Signaling Inc.