DART is continuing to work through the design of a new Downtown Dallas subway. There’s lots to consider. In a previous post we looked at geology. In this post we’ll consider some of the man-made elements.
- Existing Structures
DART considers existing structures when we evaluate the route for D2. By tunneling underground, DART will have to gain a thorough understanding of the foundations of buildings along the route whether it’s a large modern skyscraper or a historic building. These large structures are similar to icebergs. Many times a large portion of the building foundations are underground in order to support the weight and functionality of the larger structure we see above the surface. Making sure that our underground tunneling efforts do not damage or disturb these building’s foundations will be another priority DART will consider as we assess D2’s future route.
- Utilities and Underground Obstacles
Out of sight-out of mind. That’s how most of us probably feel about utilities and sources of power that flow to us every day. However, there is a buzzing infrastructure of pipes, wires and duct work, giving us the connections we need to connect us to the power we use in our daily lives. Competing for space underground are infrastructure for services like telecommunication, cable, natural gas, fiber optics, sewage system, and traffic light cables. D2 will have to make sure these elements are properly moved or relocated so that these services remain uninterrupted as construction of D2 begins.
How Does That Affect Where the Route Will Go?
Every route D2 could take has pros and cons. First, we have to consider the boundaries of where D2 can go as a Core Capacity Project. DART is competing for funding for D2 from the Federal Transit Administration (FTA)’s Core Capacity Program. While DART believes that D2 has a strong chance to win these funds, D2 must adhere to Core Capacity Program requirements, some of which require the project must:
- Be located in an area that is at or over capacity or will be in five years
- Increase capacity by 10 percent
After taking these requirements into consideration, we then can determine some initial limitations for the location and extent that D2 will run through downtown Dallas.
DART has begun narrowing down the route to approximately six or seven options, moving onto refining and evaluating these potential designs. DART is assessing each option, determining feasibility and cost, based on the factors we discussed above like soil, existing structures and utilities and underground obstacles. Additional considerations include how well the options serve existing riders while meeting future growth needs.
Making sure we consider every option and gain input from others before settling on a route is critical. Information from stakeholders, agency staff, public officials, and the public combined with DART’s technical expertise, we know that we will find the best route for D2 that is the most feasible, affordable, and reasonable.