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Compiled by Michael Popke
Lightning strikes can damage rail infrastructure and create major network issues. Surges occur in the form of direct lightning hits, but they also can be induced when overhead high-voltage transmission lines are struck by lightning. Direct strikes usually damage equipment, while nearby strikes cause damage by induction, as manufacturers of surge protection devices (SPDs) point out.
“That means the lightning current flowing nearby creates a surge current in system wiring, even though that wiring itself was not directly hit by lightning,” said Chester Kawiecki, general manager of Lightning Protection Corp., in an email. “The majority of strikes are between 10 kilo amps (kA) and 40 kA, [but] the highest can be 200 kA to 300 kA.”
Because weather is so unpredictable, railroads must employ an array of SPDs, relying on technology to undo Mother Nature’s wrath.
“Lightning protection is both an art and a science,” said Ronald Capan, principal consultant for Site-Specific Solutions Inc., in an email. “The art is implementing the science.”
Progressive Railroading recently reached out to suppliers and asked them to highlight their latest offerings that help railroads defend against — and recover from — power surges. Emailed responses from seven companies follow.
Automated Railroad Maintenance Systems (ARMS) leverages strategic partnerships to develop custom solutions for specific railroad problems. For example: When a Class I was experiencing up to three “trouble” tickets per day due to issues related to hot box detector (HBD) surge protection, railroad officials turned to ARMS, which eventually created a family of products dubbed Railroad Protection Assemblies. Working with partner Transtector, the ARMS team developed a prewired assembly of low-voltage surge protectors that use fast-acting, non-degrading Silicon Avalanche Diode technology for the HBD sensor wires. For the larger-presence detection lines, the Transtector Dual Track Arrestor was chosen, utilizing hybrid metal oxide varistors and gas discharge tubes to provide all three modes of protection needed. “The ability of the Transtector devices to turn so fast has significantly contributed to the elimination of HBD problems for [Norfolk Southern],” said Dave Nelson, account manager for Transportation Products Sales Co. (TPSC), which represents ARMS products and services to the rail industry. ARMS and the TPSC sales team are working to bring these surge-protection solutions to other railroads, company officials said.
HUBER+SUHNER Inc. offers a DC and DC-DC block portfolio for the railroad market. DC blocks feature a disconnected inner conductor, and DC-DC blocks feature disconnected inner and outer conductors. They are bidirectional coaxial components that block the large voltage rises and high-amplitude/low-frequency surges that occur during regular electric railway operation. Electric railways generate significant magnetic fields, resulting in interferences that are coupled into metallic conductors that include communications lines. DC and DC-DC blocks are broadband in design and therefore available across a frequency range of 140 MHz to 2,500 MHz, company officials said. The waterproof blocks also protect against earth loops and galvanic corrosion due to stray and reverse currents in DC railway systems. They are maintenance-free, can easily be mounted and are grounded by flange connection, HUBER+SUHNER officials added.
PolyPhaser and Transtector Systems — both part of the Infinite Electronics’ family of brands — offer high-performing surge protectors designed to meet railroads’ needs. With a focus on fast-acting, non-degrading protection for RF, DC, AC and signal applications, the companies provide solutions for every Class I and major North American transit system, according to Infinite Electronics.
PolyPhaser engineers its RF protectors with non-degrading components, eliminating the need for regular replacement or maintenance. Typical rail installations include PolyPhaser VHF50-HN SPDs for 160MHz voice radio applications. These components are part of more than 15,000 positive train control base stations nationwide, company officials said. PolyPhaser DGXZ units protect thousands of GPS systems, while PolyPhaser TSX-NFF components installed in cellular networks ensure the reliable transmission of vital data to control hubs.
Transtector track and signal protection solutions are designed to help railroads improve safety and reduce downtime. Its line of DIN rail-mounted modular, high-performing DRI, DTA and DSA track circuit and signal line protectors keep trackside equipment protected and enable railroads to monitor protection remotely.
Lightning Protection Corp. designs, develops and manufactures lightning and surge protective devices. The company’s line of railroad products includes AC power circuits; track, line and yard arresters with fail-safe mechanisms; DC power; and RF co-axial lightning and surge arresters.
Railroad communications and signals operate at relatively low DC and AC power voltages and utilize RF coaxial communication signals. For protection against failure of equipment from harmful surges, these systems require effectively designed SPDs that provide all-mode protection to keep the system safe, company officials said.
Protection is provided between each line and neutral, each line and ground, and neutral to ground. The SPD rating must be for a minimum of 160,000 amperes to achieve reliable protection — a standard that Lightning Protection products meet, company officials said.
nVent ERICO’s Rail Transient Barrier (RTB) products are designed to protect against damaging voltage surges and transient events. In November, the company plans to launch RTBN, its “next generation in rail data and signal surge protection,” nVent ERICO officials said.
RTBN builds on the legacy of RTB products while adding features and functionality to meet the needs of modern railroads. It boasts a maximum surge rating of 40kA 8/20 (the nominal surge rating is 20kA), and RTBN’s DIN rail grounding connection eliminates the need for additional wires, company officials said. It also features a latching surge module designed to minimize issues caused by vibration and human error.
Other new features include a thermal disconnect for safe failure, visual status indicators and remote monitoring — all of which now are standard predictive maintenance functionalities, company officials said.
Siemens Mobility Inc. recently introduced a new SXRR advanced transient surge suppression technology to improve the protection of electronic devices and control systems. Utilizing Silicon Avalanche Diode components, the surge suppression devices fire at low voltage and are quick to respond, company officials said.
Due to the stability and reliability of the Silicon Avalanche Diodes, the use of line-to-line equalizers is not required for the SXRR surge suppression technology, Siemens officials said.
Site-Specific Solutions Inc. has provided lightning protection, power supply products and consulting services to the rail industry since 1998. Products are designed to be user friendly, reliable and cost effective, company officials said. Products currently are used by freight and passenger railroads.
The product line provides AC and DC power protection, as well as line-to-ground protectors and power supplies that are double-stage protected.
The company’s most popular AC line protector is the Model SSS-120/240VAC-AM for the normal signal house feed of 120/240VAC, officials said.
The company’s DC protector selection spans simple discrete components packaged for easy installation per customer requirements to SSS indicating protectors, which show real-time protection status. Additionally, the products are designed and packaged for harsh environments, and they are developed with the goal of zero failures, according to the company.
Michael Popke is a Madison, Wisconsin-based freelance writer. Email comments or questions to email@example.com.