Canadian National Detector Overview

In the 1980s, CN developed their own overlay talker system for existing Servo installations using the Z80 microprocessor. Bilingual units were used in Quebec on lines where English-speaking crews would operate.

On former GTW lines, CN reprogrammed the GTW-era Harmon Model 75s to announce Canadian National.

The MicroHBD is CN's current preferred detector model, and have been for the past 20 years or so. Virtually every detector in the United States is a MicroHBD, although STC units do remain in operation in Canada.

To learn how to identify whether a detector is a MicroHBD or an STC Sentry 2100, see the section below on the STC Sentry 2100.

CN inherited some Sentry 2058 units when they took over the Wisconsin Central and Algoma Central, some of which were reprogrammed to say CN. These units retained the standard voice in lieu of the custom Canadian voice featured on the Sentry 2100.

In the early 2000s, CN installed numerous detectors with STC Type 2 bearing scanners. Due to the timeframe and the scanners used, they can only be STC Sentry 2100 units - the Sentry 2058 used different bearing scanners, and the SmartScan NG was not introduced until 2004.

These units sound extremely close to the MicroHBD units that CN used with the same exact voice in Canada. The easiest way to tell the difference is to look at the bearing scanners themselves at each installation. Furthermore, the Sentry 2100s tend to be HBD-DED only sites while the MicroHBDs tend to also include HWD capabilities, although this is not the case 100% of the time. Transducers are interchangeable between manufacturers, so it is not uncommon to see GE/Progress Rail transducers being used with an STC detector (sometimes mixed & matched with STC transducers).

To identify them by audio only, there are some subtle differences to pay attention to. Perhaps the easiest way to discern them is the tone at the beginning: the Sentry 2100's is slightly lower pitched and stops transmitting briefly after the tone, whereas the MicroHBD's tone is slightly higher pitched and keeps transmitting. The STC 2100 also has a slightly slower pace and quieter audio, as well as saying numbers 5, 7, & 9, and "Total Axle" differently than the MicroHBD. For French-speaking detectors, the Sentry 2100s say "Essiuex Total" while the MicroHBD says "Total Essiuex" for the axle count.