Audio Frequency Train Activated Circuit - AFTAC™ II

The AFTAC™ II (Audio Frequency Train Activated Circuit) is the second-generation FM audio overlay train detection system – offering a compact, flexible solution for a wide range of applications.

Key Features

• Vital solid-state design
• Configurable approach timing for flexible applications
• Rugged construction for long service life

Customer Benefits

• Enhances grade crossing safely with precise train detection
• Simplifies installation and reduces field adjustments
• Improves reliability and lower lifecycle maintenance costs

One System. Four Configurations.

Housed in a single enclosure, the AFTAC™ II can be configured in four different ways: as a single transmitter, a single receiver, one transmitter with one receiver, or two receivers. The system uses only two modules for receiver configurations and one module for a single transmitter setup. With proper coupling, both the transmitter and receiver can operate over the line – no insulated joints required.

Output power is managed through a three-position power level switch and a six-setting power range jumper.

• Low power (up to 0.5 VAC) is suitable for short distances up to 2,500 feet, depending on frequency and ballast conditions.
• Medium power (up to 3.18 VAC) supports longer distances up to 4,500 feet.

Designed for performance and flexibility, AFTAC™ II reduces hardware requirements while maintaining reliable train detection capabilities.