Rail noise grade separation alternative analysis case study

The San Francisco Bay Area has an existing commuter rail system that brings commuters from southern regional communities into the downtown city center. One of the communities served by commuter rail service is the City of Palo Alto, CA, which includes four active grade crossings, each requiring train horn sounding for each train event. The City wished to evaluate various options to eliminate the noise generated from horn soundings by creating road/rail grade separations at each existing grade crossing and other possible noise and vibration control elements. The alternatives included crossing closures, rail bed trenching, viaducts, roadway underpasses, and tunnels. A noise and vibration study was undertaken to provide an analysis of which alternatives would provide better reductions in noise and vibration in the surrounding community. The study included an assessment of existing noise levels and predicted future noise and vibration levels for construction and operation of each proposed alternative using current established noise and vibration methodology. The results of this study included comparisons of the noise and vibration associated with each of the of the proposed alternatives that could be used in conjunction with other studies considering cost, traffic, safety, aesthetics and other factors to select an overall preferred alternative.

Evaluating Financing Mechanisms and Economic Benefits to Fund Grade Separation Projects

Investment in transportation infrastructure projects generates benefits, both direct and indirect. While emissions reductions, crash reductions, and travel time savings are prominent direct benefits, there are indirect benefits in the form of real estate enhancements that could pay off debt or loan incurred in the improvement of the infrastructure itself. Studies have shown that improvements associated with rail transportation (such as station upgrades) trigger an increase in the surrounding real estate values, increasing both the opportunity for monetary gains and, ultimately, property tax collections. There is plenty of available guidance that provides blueprints for benefits calculations for operational improvements in rail transportation. However, resources are quite limited in the analysis of benefits that accrue from the separation of railroad at-grade crossings. Understanding the impact of separation in a neighborhood with high employment or population could generate revenues through increased tax collections. In California, the research need is further amplified by a lack of guidance from the California Public Utilities Commission (CPUC) on at-grade crossing for separation based on revenue generated. There is a critical need to understand whether grade separation projects could impact neighboring real estate values that could potentially be used to fund such separations. With COVID-19, as current infrastructure spending in California is experiencing a reboot, an approach more oriented to benefits and costs for railroad at-grade separation should be explored. Thus, this research uses a robust benefits-to-cost analysis (BCA) to probe the economic impacts of railroad at-grade separation projects. The investigation is carried out across twelve railroad-highway at-grade crossings in California. These crossings are located at Francisquito Ave., Willowbrook/Rosa Parks Station, Sassafras St., Palm St., Civic Center Dr., L St., Spring St. (North), J St., E St., H St., Parkmoor West, and Nursery Ave. The authors found that a majority of the selected at-grade crossings analyzed accrue high benefits-to-cost (BC) ratios from travel time savings, safety improvements, emissions reductions, and potential revenue generated if property taxes are collected and used to fund such separation projects. The analysis shows that with the estimated BC ratios, the railroad crossing at Nursery Ave. in Fremont, Palm St. in San Diego, and H St. in Chula Vista could be ideal candidates for separation. The methodology presented in this research could serve as a handy reference for decision-makers selecting one or more at-grade crossings for the separation considering economic outputs and costs.

High Prevalence of Superior Labral Anterior-Posterior Tears Associated With Acute Acromioclavicular Joint Separation of All Injury Grades

Background: Despite the relatively high number of cases of acromioclavicular joint (AC) separation in the athletic population, optimal clinical outcomes are not achieved in every case. Limited data exist regarding the prevalence of intra-articular glenohumeral pathologies (IAPs) associated with acute AC separation of all injury grades. Purpose: To determine the prevalence of IAPs associated with AC separation, regardless of severity. Study Design: Case series; Level of evidence, 4. Methods: A total of 62 patients (mean age, 37.6 years) with acute AC separation were included in this study; 41 were nonoverhead recreational athletes. All patients underwent magnetic resonance arthrography (MRA) to evaluate for IAPs. Arthroscopic data from patients undergoing surgical treatment were correlated with MRA results. Results: Patients sustained acute AC separation of Rockwood grade 1 (16.1%), grade 2 (46.8%), grade 3 (25.8%), and grade 4 (11.3%). A concomitant IAP was present in 48 of 62 (77.4%) patients and included superior labral anterior-posterior tears (72.6%), anterior labral tears (24.2%), posterior labral tears (4.8%), supraspinatus tears (3.2%), and inferior glenohumeral ligament ruptures (1.6%). There were 18 (29.0%) patients who had a concomitant pathology in >1 intra-articular structure (combined IAPs). Additionally, 71.8% of patients with grade 1 and 2 AC separation had associated IAPs, and 23.1% had combined IAPs. Furthermore, in patients younger than 40 years, 64.0% of those with grade 1 to 3 AC separation demonstrated associated labral pathologies. There was no difference when comparing age or severity of AC separation and the prevalence of concomitant labral tears ( P = .36 and .22, respectively). Conclusion: There was a high prevalence of IAPs among patients undergoing MRA after AC separation. While an IAP has been described in association with high-grade AC separation previously, the high prevalence of IAPs in low-grade separation in our study was unexpected and suggests that a thorough evaluation and clinical follow-up for patients with all grades of AC separation may be beneficial.

Socialising on a Skywalk: How Hong Kong’s Elevated Walkways Become Public Open Spaces

In high-density Asian cities, the increasing scarcity of public open spaces gives rise to the need for stationary activities to tap into spaces originally conceived exclusively to channel pedestrian movements, such as grade separation pedestrian systems. However, the types and patterns of stationary activities on elevated walkways remain mostly unexplored. This study focuses on Hong Kong, wherein the scarcity of public open space characterises an extreme condition and where the burden of this scarcity falls most heavily on disadvantaged social groups, such as migrant workers. The findings highlight the prevalence of socially oriented activities and the importance of food as a gathering factor.Keywords: Grade separation pedestrian system; Elevated pedestrian network; Public open space; Migrant domestic worker; Hong KongeISSN 2514-751X © 2020 The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/aje-bs.v5i15.361

Separating Poor Playmates: Untangling Commuter Rail from Freight

North American commuter railroads run their trains largely on tracks shared with freights (and in the northeastern US, often shared with intercity passenger trains). This sharing makes commuter rail relatively affordable to implement. However, as freight traffic grows, so does the potential for delays. If freight and commuter operations affect each other’s performance, it may be necessary to consider separation measures, not adding to the existing shared-track capacity. Temporal separation can work on low-volume operations. Busier lines may require physical separation, which can be implemented in several forms for trunk lines (grade separation at junctions, freight bypass, partial trunk line separation, and full trunk line separation), as well as physical separation in downtown areas. This article identifies these separation options, describes their attributes, presents representative examples, and outlines criteria for evaluation.

Patterns of Stationary Activities in the Elevated Pedestrian Networks of High-Density Asian Cities: The case of Mong Kok, Hong Kong

Urban areas are increasingly failing to provide citizens with adequate and quality public open spaces. In this regard, Hong Kong characterises an extreme condition with 2.7-2.8 m2 of open space per capita. The burden of this scarcity falls most heavily on economically disadvantaged social groups, such as migrant domestic workers. In this context, grade separation pedestrian systems that were originally designed for mobility purposes, can provide space for sociability-oriented stationary uses. This study finds that the density of stationary activities in a typical elevated pedestrian network is as high as 1.2 person/m2.Keywords: Skywalk; Behavioural mapping; Stationary uses; Hong KongeISSN: 2398-4287 © 2019. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/e-bpj.v4i12.1905