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DART Orange Line

Bridgefarmer & Associates, Inc. was a lead design engineer for the 9-mile DART Orange Line Light Rail Project and Engineer of Record for more than half of the overall project. This is the first ever design build project let by DART, beginning at Northwest Highway leading to the DFW Airport and running parallel to SH 114.

The Bridgefarmer team, due to its vast experience with rail, DART, and its

history of working on the SH 114 corridor, was instrumental in securing

this contract. The Northwest Corridor for DART’s new alignment crosses

over the Trinity River. A Minor 408 Permit was required from the USACE

to cross the Trinity River levees; and relocation of City and Franchise

utilities were scheduled to meet a very tight delivery.

  • One of the biggest challenges on the project was the layout of the proposed bridge between the Trinity River levee and the overhead Oncor power lines. Bridgefarmer developed a special bolt up girder design for the levee crossings. To reduce the construction depth, the bolt up section was used to meet the clearance requirements. 

  • Work in the vicinity of the levee required complex hydraulics and modeling tools                              to be utilized to design for the discharge and the required mitigation. This work had to be done following levee requirements while paying close attention to structural details related to special light-rail electrical requirements.   

  • Another significant achievement for Bridgefarmer was the design of precast panels for the DART light rail bridges.  Bridgefarmer championed the acceptance and implementation of the precast panels by DART.  This innovative design was used as a DART standard throughout the Orange Line project and saved millions of dollars in construction costs.

  • Eight bridges totaling approximately 14,000’. The longest of which is the Trinity River Bridge at nearly 7,500’. The Trinity River Bridge spans over a major intersection in Dallas, Interstate 35, two levees, and the Trinity River. The Trinity River Bridge includes the use of the longest pre-cast concrete girders ever erected in Texas.


Section I-1 and I-2 as one contract measured over 9 miles and consisted of 3 miles of light rail guide way bridge structure with the track directly fixed to the bridge deck and 4,360’ of retaining wall.  Bridge structures were analyzed for the rail force interaction and application of DART light rail loading.  Several straddle bent caps, each over 100’ in length, were post tensioned to carry the applied loads. The final leg of the expansion, I-3 completes the Orange Line to DFW International Airport. Bridgefarmer designed a one-mile section of I-3, which included three bridges with retaining walls over Beltline Road, a major electrical transmission corridor, and a major drainage system. Designs were completed on schedule and within the allocated budget as bid. All contract scheduled milestones were exceeded.

Project Construction Cost Estimated: $600 Million

Client: DART

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