Model Parameter: Station Box

  1. Constraints
    • Box Width [m]
      The station box width is defined by the cumulative spatial requirements of internal physical constraints, including standardized track width and required platform width. In addition, minimum spacing between tunnel axes is incorporated, with this area allocated for utilities where appropriate. A track gauge of 1,435 mm (standard gauge) is assumed1, and adjacent metro lines are represented in the model using simplified rectangular geometries.
      Due to the standardized dimensions of train tracks and the fixed requirements for platform widths, the station box width is treated as a fixed constraint within the model and is not varied as part of the design exploration.
    • Platform Geometry and Position
      The platform geometry must align precisely with the locations of vertical access elements connecting to the above-ground building. As such, platform positioning constitutes a hard geometric constraint, restricting the placement and configuration of both the station box and the associated access infrastructure.
  2. Design Variables
    • Box Depth & Height [m]
      For cut-and-cover construction, the practical depth range of the station box typically lies between 30 and 40 feet (approximately 10 m to 12 m)2. This range is influenced by the design of excavation support systems, which are temporary structures required to ensure safe working conditions, enable construction activities, and protect adjacent buildings, utilities, and infrastructure. Based on these considerations, the station box depth (and corresponding box height) is defined within the model as a design variable with an allowable range between 10 m and 12 m. Configurations approaching the upper bound of this range require careful evaluation due to their increased impact on soil settlement affecting nearby structures, as well as higher financial, constructional, and operational burdens3.
    • Box Length [m]
      The length of the station box is directly related to train length and the number of carriages, which together determine passenger capacity. According to the Metro Rail Design Criteria, Section 9 (Systems), vehicle lengths typically range from 22.8 m to 27.14 m, with widths between 2.65 m and 3.15 m4. As a reference, several metro stations in Berlin were measured, yielding an average platform length of approximately 100 m. Passenger density is assumed to be 4 passengers per square meter (pax/m²), representing an intermediate value within the range reported by Tirachini et al.5.
      Within the model, the station box length is treated as a design variable that can be adjusted within a defined and realistic range informed by these references, allowing the exploration of different train configurations and associated passenger capacity scenarios.
Model Parameter: Metro StationModel Parameter: Tunnel
Model Parameter: Precast Concrete Facade System & External Thermal Insulation Composite System (ETICS)Model Parameter: Storm Water Vault
Integrated Parametric ModelResults Analysis: Design Exploration

References

  1. RollingStockWorld. (2024, May 21). Talgo Avril high-speed EMUs have entered service in Spain. RollingStockWorld. https://rollingstockworld.com/passenger-cars/talgo-avril-high-speed-emus-have-entered-service-in-spain/ ↩︎
  2. U.S. Department of Transportation, Federal Highway Administration. (2009). Technical Manual for Design and Construction of Road Tunnels — Civil Elements (Pub. No. FHWA-NHI-09-010). https://www.fhwa.dot.gov/bridge/tunnel/pubs/nhi09010/tunnel_manual.pdf ↩︎
  3. Tavallaie Nejad, A., Salari Rad, H., Behnia, C., & Mohammadi, D. (2022). Comparative Study on the Design Process of a Shallow Subway Station Isfahan Metro, Iran, Based on Risk Assessment. Indian Geotechnical Journal, 53(1), 562–582. https://doi.org/10.1007/s40098-022-00691-3 ↩︎
  4. Los Angeles County Metropolitan Transportation Authority. (2013). Metro Rail Design Criteria, Section 9 / Systems(Revision 6, June 26, 2013). https://partners.skanska.com/usa/clients/lametro/WSE/PreBid/OwnDoc/RFP/Addenda/Amendment%201/Vol%20II%20-%20Project%20Definition%20Documents/2.MRDC/Metro%20Rail%20Design%20Criteria%20Sect%2009%20Rev%206%20062613.pdf ↩︎
  5. Tirachini, A., Sun, L., Erath, A., & Chakirov, A. (2016). Valuation of sitting and standing in metro trains using revealed preferences. Transport Policy, 47, 94–104. https://doi.org/10.1016/j.tranpol.2015.12.004 ↩︎