GPON Is the Engine


Amtrak HQ Project Choo-Chooses Passive Optical LAN —

Even before Amtrak began the renovation of the National Guard Building, which would become its new 82,000 sq. ft. headquarters in Washington DC, the national railroad was determined to create a state-of-the-art facility. Its goal was to create one of the most modern and sophisticated telecommunications systems available today in order to meet its present and future telecommunications requirements.

Among the highest priorities was a converged network capable of providing high-bandwidth and wireless connectivity for up to 500 users housed throughout the 4 floors of newly remodeled office space. A fiber optic network was the obvious choice to achieve these requirements, so Amtrak and its consulting engineers selected passive optical LAN due to its affordability, reliability, long life, and reduced power consumption.

Passive optical fiber networks (also known as PON, POL, GPON, and OLAN) are widely recognized as a solution to eliminating data bottlenecks and to leverage a cabling infrastructure with unlimited bandwidth potential. They are also simpler, hence easier to configure and with a smaller footprint. In addition, they are capable of protecting high-security communications through advanced data encryption. Plus, they provide major cost savings over traditional networks, are easily expandable, and are greener with significantly fewer energy and cooling/ventilation requirements.

GPON is transforming the Amtrak IT ecosystem into a highly resilient and scalable network aligned with future technology objectives. VT Group, a global systems integrator, chose Aaron Reale, RCDD and Director of Operations, to help since he designed the optical networks at several other Amtrak locations in the past.

The solution Reale recommended for the new facility was a Gigabit-capable PON (GPON) fiber network, a high-speed version of basic PON that provides high-bandwidth in both directions (e.g., 2.48 GB/s of downstream and 1.24 GB/s upstream). GPON is a more robust form of increasingly popular PON networks (also known as POL, passive optical local area networks) that are composed of point-to-multipoint fiber conducted through unpowered (passive) optical splitters. “The GPON solution utilizes a cable containing a single strand of single-mode fiber capable of providing hundreds of users unlimited bandwidth,” Reale explained.

These passive networks enable enterprises to simultaneously converge multiple services such as data, voice over Internet protocol (VoIP), video conferencing, building security, management services, and wireless devices — applications that are today choking many enterprises’ copper- or Ethernet-based telecommunications capabilities. In addition, similar to optical services such as Verizon’s Fios®, these networks can easily be expanded simply by adding nodes to a cable containing a single strand of fiber.

Power Challenges
Because Amtrak has operations at many historical sites, such as Baltimore’s Penn Station and Washington DC’s Union Station, the company has too often experienced highly disruptive power outages. Therefore, maximum uptime and reliability were of paramount importance for Amtrak headquarters.

For the project, Reale selected a hybrid fiber/copper cable solution from Optical Cable Corporation (OCC) to eliminate this risk by consolidating all fiber and power cabling for all telecommunications to a single, protected space with fully redundant battery backup. The Slimline Hybrid cable has a single strand of bend-insensitive single-mode fiber that provides unlimited bandwidth, plus two 18-gauge copper wires to carry electrical power to each work area outlet.

Because of the inherent drop in voltage that occurs over copper wire, Reale’s team also incorporated digital electricity to enhance transmission performance. This emerging technology combines DC power and data into packets which are transmitted and received in a manner that is somewhat analogous to how information packets are conveyed over networks.

“Digital electricity allows us to push power out to much longer distances without having to plan for the normal voltage drop — and without having massive copper wire size,” said Reale. “We incorporate this technology into our designs when centralized power is a must, and on projects when the facility’s design doesn’t support traditional cable lengths, such as rail stations, airports, and sports venues.”

Smaller Than a Rail Car
While Amtrak’s new headquarters are expansive, every inch of space is accounted for operational use. One of the significant savings in using the passive optical network is gaining a considerable amount of space from what would have been utilized for telecommunications rooms.

Traditionally, with a four-floor space like this, the team designs eight 10×12-foot telecommunications closets, build out with racks, cabinets, and other equipment. Each closet requires a UPS battery backup, plus additional HVAC cooling because of the addition of concentrated heat within the space. Putting that all together involves a lot of setup costs and a lot of recurring costs.

Instead, just 1 telecommunications closet with 2 racks will support all the users, significantly reducing the footprint. Real estate prices in Washington DC make this a very expensive space, so any additional square footage that we can give back for operational use is immense in the long term. So, rather than taking up 1,000 sq. ft. for telecommunications closets, this system is taking up just 100 sq. ft. The rest of the system utilizes much smaller pathways and light loads to distribute connectivity throughout the entire facility.

In order to eliminate the additional telecommunications rooms, VT Group designed and built customized Zone Enclosures which mount above the ceiling and act as infrastructure distribution nodes.

Staying On Track
While GPON technology has been around for a few decades and used heavily by the large telecommunications carriers, many stakeholders are just beginning to become familiarized with its benefits in an enterprise local area network.

This type of solution has really received meaningful attention only recently. However, it is the right long-term solution for many of today’s companies, and more designers and users are seeing the ROI and other gains that can be realized by adopting it.

For more information about:
OCC, please email or visit
VT Group, please visit



About Author

Ed Sullivan is a Hermosa Beach, California-based writer. He has researched and written about high technologies, healthcare, finance, and real estate, for more than 25 years.

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