Washington, DC

This project involved the design and permitting of 0.5 miles of dual circuit 115kV transmission in Washington DC.  This project was to support the installation of a new pedestrian bridge to the Minnesota Avenue Metro Station, which required removal of electrified railway conductors no longer in service and raising of the two transmission lines.  Due to operational restrictions, the work had to be designed so that one transmission line stayed in service at all times.

The existing circuits were located on electrified railway catenary structures that spanned over 4 active railways.  All materials had to be designed such that that they could be brought in via flatbed railcars and installed using high-rail mounted equipment.  Due to the close proximity of the transmission structures to CSX Railway and to tunnels, tracks, and a metro platform owned by WMATA, all foundations had to be designed such that no excavation and no impact or vibratory pile driving would be allowed.

The structures were analyzed using a combination of PLS-CADD and STAAD to determine which structures needed replacement and which structures could be modified for the increased loads.  Custom helical pier foundations were designed that could be installed from high-rail equipment and meet the limitations set by CSX and WMATA.  Detailed construction work plans and calculations packages were submitted to CSX and WMATA to demonstrate the line would exceed their Cooper E-80 railway loading requirements, would not overload their existing tunnels or retaining walls, and provided detailed work processes and schedules of when each rail line or metro track would require signaling, single tracking, or full outages.  All work was coordinated with DDOT also, since they were responsible for the pedestrian bridge construction and needed to utilize the temporary at-grade rail crossing and utility rail spur for their foundation installation as well.






Please contact David S. Huffstetler at 919.851.8770 for more information about our Transmission Services or email


Line Voltage

Dual Circuit 115kV

Length of Project

0.5 miles

Engineering Challenges

Constructions overhanging Railroad, Proximity to WMATA tunnels and retaining walls, Modification of existing catenary structures


Raleigh, NC

2300 Rexwoods Drive, Suite 300
Raleigh, NC 27607

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400 Redland Court, Suite 200
Owings Mills, MD 21117

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9300 Harris Corners Parkway, Suite 460
Charlotte, NC 28269

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Summerville, SC 29486

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Katy, TX 77494

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9342 Lindale Ave
Baton Rouge, LA 70815