Interlocking Solutions

VPI II Overview Nov 13 5 MB


VPI II Installation, Operation and Theory Nov 13 317 KB

P2511B V1

VPI II Chassis Nov 13 1.35 MB

P2511B V2

VPI II Vital Subsystem Nov 13 1.31 MB

P2511B V3

VPI II Non-vital Subsystem May 11 945 KB

P2511B V4

VPI II Maintenance and Troubleshooting Nov 13 907 KB

P2511B V5

VPI-II, iVPI AlsDload
Nov 13 74 KB     
VPI-II, Data Logger
Mar 08
350 KB
VPI/CAA Reference Manual Jun 14 5.4 MB


CAAPE User's Manual Nov 13 1 MB


MMS - Maintenance Management System Manual Dec 13  1.6 MB


  • High availability, partitionable with redundancy MTBF in excess of 100,000 hours
  • Flexible configurations from very small to very large applications
  • Controls interlockings with up to 35 switch machines
  • Modular design — from single module to pre-wired case to bungalow packages with switch machines and signals
  • High degree of sub-system integration: Automatic Train Protection (ATP), Automatic Train Supervision (ATS), and Train-to-Wayside Communication (TWC)
  • Forward and backward compatibility
  • Supports migration to larger systems including CBTC and PTC

With more than 1000 installations in 14 countries, VPI II is the industry leader in safety and reliability. Based on VPI technology which has been in service since 1986, there have been no unsafe failures; an unblemished record of VPI Controlled Vital System Operation in excess of 72,000,000 hours.