Author: Ze Customer Service

Audio Overlay Best Practices

Relevance: This app note applies to the Z3 Plus, PD8 Plus module and the discontinued ZEPICIII, PD8 module.

Purpose: The purpose of this App note is to emphasize long held rail industry best practices for installing audio overlay track circuits. It is useful to periodically review this material to insure proper installation and maintenance for audio overlays whether installed by railway personnel or 3rd party contractors.


  1. Insure that the operating frequency of the audio overlay is compatible with the operating frequency of all other
    equipment on the same track and neighboring tracks, if applicable.

  2. Use properly rated primary surge protection and ground rods. See relevant AREMA specifications.

  3. Periodically inspect primary surge protection for wear due to surge activity. Reduced effectiveness of primary protection can expose secondary protection to excessive surge levels resulting in equipment failure.

  4. Use twisted # 6 bond strand for track wires between rail connections and the overlay unit. Audio overlays are generally used in switch unlock, DED and AEI presence detection applications. As such, these products may be located near crossings and within signal system circuits. If a short circuit were to occur in the track wires or surge protection or house wiring, the signal system would be put to stop due to the low resistance of #6 track wires, calling attention to the affected area.

  5. Monitoring diagnostic data provided by DED and AEI systems will facilitate the prompt and efficient maintenance of audio overlays.

  6. The product user manuals for these products have been updated to include a simple shunt test to work hand in hand with best practice installation methods detailed in this app note.

  7. Check zukinut.com often for current user manuals, installation tips and troubleshooting procedures.

ZEPIC6 Clearance Track Circuit

The ZEPIC6 is a new and innovative approach to solving the most challenging clearance track circuit applications.

This product provides two independent track drive outputs with the provision of sub-dividing the respective CTC into 2 circuits. In total, a single ZEPIC6 is capable of providing 4ea track circuits. The empty circuit limits are defined by a hard wire shunt located at the entering end and a Zukinut supplied inductive shunt at the DTC end. Using a center fed arrangment, the ZEPIC6 can pick cleared circuits behind a moving car, allowing faster access to diverging routes of following moves.

Diagnostic troubleshooting codes with built-in push buttons and display.

All user configurations stored in non-volatile memory.

Compatible with Z-Tools

Customer Support Services

Building on the momentum of 2015, the Zukinut partners decided to invest in new processes, procedures and infrastructure moving forward into 2016 and beyond. The focus of this effort was to create a more efficient organization with an emphasis on customer responsiveness, improved access to Zukinut product information and support. Mid year we are happy to announce the following accomplishments:

Our new phone system provides direct  lines to customer service and engineering. Voicemail along with emailed notifications provide improved customer/vendor follow-up.

Customer support desk. This on-line service is available 24/7, free of charge and allows customers access to product manuals, application notes and training videos. Support tickets can submitted requesting product support, RMAs and order status.

Check the News section of zukinut.com regularly for announcements of new products and services along with upcoming Zukinut product training events.