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July 2012 www.sname.org/sname/mt Port area main tracks were modeled based on length, ability to support concur- rent train movements, and estimated travel times. is was valid for this analysis because it is only possible to travel at 5 mph in this area on these kinds of tracks, and there are safety practices that limit the number of simultane- ous movements (see Figure 1). For the purpose of this model, what was important was not the details of how this would be achieved, but that it was feasible to do in a nal design. (Of course, assumptions like this must be documented and reviewed later in the project to ensure that the chosen design is able to meet them.) Note also that this approach enabled the analysts to easily investigate the e ects of single versus double tracks in di erent areas. e model run time to get results for this port-wide model was just seconds. is allowed sensitivity analysis to be performed for other variables, such as inspecting trains at PBY instead of at the marine terminals, and mixed destination versus single destination trains. Stage 1 model conclusions The results of the stage 1 model runs indicated that at 2020 and 2030 projected vol- umes, the number of arrival and departure tracks in use occasionally exceeds the num- ber of 10,000 ft. tracks that can physically be built in any of the concepts (see Figure 2). Also, the number of storage tracks needed sometimes grows beyond what can prac- tically be built. is implies that, at times, special strategies will need to be developed and used to handle the extra volume. ese became a focus of the stage 2 model. e stage 1 analysis also provided insight into other POLB pinch points. It highlighted that a major rail intersection near the entrance to POLB (the Crucero Diamond) will likely become a constraint if the rail in that area is not designed to accommodate more than one train at a time. The stage 2 model After the stage 1 modeling, the concepts with a mini intermodal container yard were eliminated, as it was clear that all available space is needed to support on-dock rail activity. e remaining concepts for pier B fell into two basic families. One family of concepts assumed the largest possible yard, with 5 long arrival/departure tracks (the ?12th Street option?). It would require signif- icant property acquisition, and depends on the relocation of the 710 freeway (a separate project). e second family was of smaller yards (the ?10th Street option?). Although they would have less capacity, they also require less property acquisition. e two alternatives represented di erent political and/or economic choices. Because even the 12th Street option was smaller than ideal, it seemed likely that some trains would have to be held out of the pier B area until space became available. If they were held out too long, the delay would a ect the throughput at the marine termi- nals. Similarly, loaded cars might have to wait in a marine terminal for space in PBY, with equally detrimental e ects. us, the question for the stage 2 model became, ?how much volume can be handled via on-dock rail with a yard of how many tracks?? e stage 2 modeling e ort built upon the stage 1 model. It provided the ability to compare and measure the bene ts of the e modeling team and engineering team worked together to develop a three-phase ?building block? modeling approach. The Hanjin Shipping facility at the Port of Long Beach. FIGURE 2: STAGE 1 A-D TRACK USAGE DETAILS FIGURE 1: EAST BASIN SCHEMATIC WITH TRACK CAPACITIES