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3/2/2017
PacStar Perspective: Creating a stable infrastructure for IP-based train-control technology

By Steve Bowen, Senior Commercial Business Development Manager for PacStar (Pacific Star Communications Inc.)
Advanced IP-based networks are moving railroads into the future. With greater control and faster communication, these technologies have the potential to improve system reliability and allow problems to be detected and resolved sooner. Reaping these benefits, however, requires the deployment of networking equipment in extremely harsh environments.
In the past, train control technologies have been deployed broadly by many railroads that installed dial-up/analog 96k modems, and despite the many limitations of this approach, it is still being used. However, most telecommunications providers are dropping support for dial-up leading to a need for a better alternative based on enterprise-class IP-based network technology. The upside is that higher-performance networks also improve reliability and allow the use of more sophisticated applications and greater automation.
A key challenge to making this move, however, is the extreme cold or hot weather and vibration found in wayside locations. This is becoming an especially significant problem with the growing use of intermediate signaling locations such as that shown below, which are smaller and typically lack environmental conditioning.
Standard enterprise routers and networking equipment usually is not sufficiently rugged for in-field use. This is particularly true of communications equipment designed for office and datacenter environments where the devices are intended to be rack mounted and run in air-conditioned environments. Among the most significant challenges for railroad applications are vibration from passing trains and extreme heat and cold. For example, a typical commercial server has an operating temperature range of just 10°C to 35°C, while equipment designed for more extreme conditions can handle anything from an arctic-like -20°C to a sweltering 60°C.
Typical devices also struggle under “dirty” power conditions that are often prevalent in remote wayside bungalows and intermediate signaling locations. This is particularly true for the types of devices that run in offices and rely on conditioned utility-provided power. Equipment used in remote industrial applications must be designed with power supplies that work reliably, and must protect against power spikes and poor quality power.
Enterprise devices are also not designed to meet highly space constrained installation locations. Often, industrial IT installations have little available room for additional equipment. For rail and train control networks that require new equipment additions, this can create a requirement to replace wayside IT cabinets.
To solve these issues and enable deployment of enterprise IT equipment where it’s needed, railroads are starting to turn military grade equipment adapted to meet specific industry needs.
PacStar is a systems integrator and manufacturer that has been in business for 16 years, designing, deploying, configuring and securing networking technology for the U.S. Department of Defense (DoD), and for first responders, universities and companies worldwide. Customers include the largest U.S. DoD tactical communications programs, the North Atlantic Treaty Organization (NATO), and other partner militaries for both classified and unclassified networks.
For these systems, the DoD requires the best available size, weight and power (SWaP), as well as security and ruggedness — making these systems also well-suited for train-control applications. As shown below, PacStar products are designed with a modular enclosure architecture, so that the modules can be easily transported and then operated right out of their chassis, together with full power conditioning and UPS backup. PacStar systems are significantly smaller than typical network servers intended for rack-mounted deployments.
There are several approaches to ruggedizing technology that the industry has adopted, some involving the use of proprietary network technologies. For most rail applications, the preferred approach is systems that incorporate commercial off-the-shelf (COTS) technology from vendors such as Cisco, Aruba, Haivision, Riverbed, Brocade, and so on — the top makers of secure, interoperable, enterprise-class technology.
The advantage of using COTS technologies is that railways have already standardized and deployed these technologies into their corporate environments. This means they don’t have to change their existing environment and can take advantage of the wealth of trained experts that they already have in-house.
Hardware reliability means fewer repairs and less maintenance, but, perhaps more importantly, it gives rail companies the confidence that they can now roll out mission-critical train control applications that require dependable communications and networking links under extreme conditions.