CSX Focuses On Two Major Projects, More Fluid Network
Introducing The Rising Stars Of 2025
From The Editor: Of Tariffs And A ‘Trade Storm’
Women of Influence in Rail eBook
Stay updated on news, articles and information for the rail industry
railPrime
12/5/2016
Smiths Microwave/PolyPhaser Perspective: Controlling RF interference caused by PTC radios
By Linda Johnson, director of marketing
RF interference caused by PTC radios operating at different frequencies is a recognized problem that railroads have acknowledged and worked to overcome since the start of PTC planning and installations. The use of high performance band pass and notch filters are currently the solution for interference for a majority of the Class I railroads and most mass transit agencies.
In 2015, a new, more complicated interference problem presented itself in the Northeast Corridor (NEC) of the U.S. where 220-MHz (ITC) radios are being used by freight railroads on the same or nearby tracks as transit trains operating their PTC (ACSES) radios at 219-MHz. These two systems operating on close frequencies and interfering with one another pose a major challenge in the railroads for on time deployment of PTC. Work was done with the FEC, channels were swapped, and some frequency separation was accomplished. This solution eliminated any actual frequency cross over from happening, but did not solve the interference problem or eliminate the need for advanced filters.
As leaders in filter technology, the U.S. railroad’s PTC engineers approached PolyPhaser about the unique problem being experienced in the NEC to provide a design solution. Working closely with the U.S. railroad industry, PolyPhaser identified the key requirements and delivered prototypes for test in June of 2016 to the Transportation Technology Center Inc. (TTCI) in Pueblo Colo.
Working with TTCI, PolyPhaser is positioned for test data to confirm shock, vibration, temperature and filtering to meet or exceed the requirements set forth by railroad industry by year end. In addition, several Class Is have completed independent testing and concluded the PolyPhaser RRF-ITC220 and RRFACE220 filters are a strong, reliable solution to the interference problem, and have begun deployment.