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Moxa’s SafeGuard™:Data Security for Mobile Platforms


As computers assume greater and greater importance in vehicular systems, specialized hardware with highly engineered data protections will be needed. Railways are an excellent example: operators are already applying information and automation technologies at every level of their service, and in rail environments extremes of heat, cold, and vibration rapidly erode commercial IT computing hardware. With computers now being integrated to facilitate customer safety and convenience, consolidate management, maintenance, and oversight, or to guarantee nine-nines of availability for remote control and communications, Moxa’s SafeGuard™ suite of technology features offer not just trains, but any mobile system a powerful industrial-grade automation/information solution.

The SafeGuard security suite for computers addresses a whole host of mobile applications challenges, overcoming problems that are simply beyond the range of commercial IT hardware. In particular, SafeGuard is tailored for the special, ever-present environmental challenges that are found on railways. The EN 50155 industrial standard was established by international bodies to clearly identify devices suitable for railway use, addressing a range of issues that include power surges and supply interruptions, vibration, heat, and more. As one of the world’s leading manufacturers of IA/IT convergence devices, Moxa has taken these international developments as its compass, and SafeGuard represents our response: a suite of data protections and tidy automations specifically tailored for rail applications, but which offer a powerful solution for any mobile environment, no matter how harsh.

Take onboard network video recorders as an example: an NVR is a software package that typically runs on a dedicated, embedded device. These computing platforms receive video streams and save them in retrievable formats; thus, they require a large storage capacity. Yet mechanical storage devices are famously susceptible to vibration and temperature extremes, and while solid-state drives (SSDs) offer much more rugged endurance with regard to vibration, high capacity SSDs are far more expensive and remain susceptible to temperature extremes. SafeGuard™ answers all of these technological challenges, and then some.

The Challenges of Train and Trackside

Computing platforms aboard ships and trains suffer because these massive vehicles are operated by massive engines overseen by relatively small crews. This means a system must be both centralized and highly resistant to temperature and vibration extremes. SafeGuard addresses these challenges in four basic ways:

  • Centralized power controls with local, automated redundancy
  • Active and passive temperature tolerance
  • Passive damping and active automation protections against vibration
  • Active and passive adjustments for inconsistencies in the power supply

Centralized Power Controls and Failsafes

Centralizing power controls involves altering the BIOS so that remote digital I/O or analog relay may be used to cleanly start up or shut down the OS. This allows the train operator to power up (or down) all computers simultaneously, so that the operator can, with only the flick of a switch, be certain that all the cabinets are on or off, as expected.

Extreme Temperature Tolerance

Active temperature protection typically means fans; however, these components introduce one more point of failure, and significantly reduce the machine’s MTBF. Moxa’s approach is to first push passive controls to their limit, by turning the entire case into one large heat sink. With appropriate materials and careful attention to the board layout, high thermal tolerance can be achieved passively, eliminating the fans.

However, when active controls are appropriately durable and reliable, they may still be used. To address more extreme temperatures, a temperature sensor is installed, with monitoring software that will cut power to the hard disk when necessary; the computer then logs new data to a solid-state, non-volatile buffer until the temperature returns to within the operable threshold.

Finally, for climates where temperatures can drop to well below zero, SafeGuard provides a fully automated onboard heater, to warm the device to an operative temperature.

Vibration and Shock SafeGuards

The effects of vibration are one of the biggest challenges for onboard computers. Solid state drives are one answer, but large capacity drives are extremely expensive, and still susceptible to heat and cold. SafeGuard’s approach is to mount industrial-grade hard disks on highly shock-resistant, asymmetrical brackets that significantly dampen resonant vibrations. This reduces displacement at the center of the drive and distributes oscillations across much more widely distributed axial dimensions, dissipating the oscillations across a wider space and significantly enhancing the drive’s already high tolerances. SafeGuard also goes further: an independent, onboard vibration sensor (G-sensor) is included, allowing operators to monitor and log conditions for later analysis. With better awareness and the drive preparations mentioned above, significant increases in MTBF are easily achieved even in vibration-prone train environments. Moreover, SafeGuard’s G-sensor is so sensitive and accurate that it may double as a site-monitoring tool, so that engineers may use it to gather environmental data about the entire station.

Power Supply Protections

Protection of and from the power supply is the last critical problem that railway systems must overcome. The first line of SafeGuard protections are optical isolators paired with power-module capacitors. The capacitors hold enough charge to carry the device through a 10 ms failure in power supply, while optical isolation provides strong protection against surges.

However, by using serial or digital I/O interfaces to pair up a Moxa computer with an unlimited power supply (UPS), further benefits are gained. A UPS may be set up to provide surge protection, power redundancy, and local power monitoring and control, all in one. When power is lost, the UPS can maintain normal operations while initializing a safe shutdown. In this way, computers which have been cut off from their regular power supply will still power down using the standard system shutdown process, guaranteeing your data and storage drives remain secure and properly synchronized.


Because of the peculiar environmental conditions introduced by motorized transport, vehicular computers—and particularly those used in railway applications—require more sophisticated and thoughtful designs than commercial IT hardware. Advanced technologies are needed to protect these computers from the conditions that inevitably arise. The SafeGuard technology suite is Moxa’s solution: automated power and vibration protections; built-in temperature and vibration sensors; and simply automated controls make SafeGuard an important element in type-approved EN 50155 systems, and a powerful feature for mobile vehicular systems of any sort.

To find out more about the technical details of the SafeGuard™ technology suite, read our whitepaper on system protections and data security for railway NVR solutions, or visit our SafeGuard microsite.

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