Railway Track & Structures - April 2008 - (Page 17)

to the fact that different algorithms will produce varying results. When choosing an engineering firm to perform or validate block designs, the customer needs to be aware of the varied design packages that are available, and to select the one that best suits their needs. The providers of these services need to make the features and descriptions of their development programs available to potential clients. Since differences between the modeling programs are to be expected, it is crucial that the customer clearly define what is meant by an “independent verification”. If the verification process is to only double-check the calculations as performed by the original block designer, then the same set of tools (modeling programs) need to be used by the checking party. Due to the proprietary nature of many of these sets of programs, the customer must make the programs available to those performing the checking or, at a minimum, identify the source and version of the programs that were used in the initial design. If the customer desires that the verification process be completely “independent” by using a different set of block design development tools, the scope of the verification process grows tremendously. Whether intentionally or not, once the use of different development tools is established, the verification process now includes a verification of the modeling algorithms in addition to the verification of the output of those algorithms. A comparison of algorithms is necessary to ensure that apples are being compared to apples, otherwise the reasons for differences in the resulting calculations are unknown, making an effective analysis impossible. The comparison of modeling algorithms is a time-consuming, expensive, and arduous process, and needs to be identified in project schedules. This is a large undertaking, and affects the project significantly. As mentioned previously, the resulting output of the www.rtands.com entire verification process (control line diagrams) is the basis of the system design. If delays are encountered during verification, or discrepancies found that require resolution, any detail designs that have been started are at risk of being incorrect and may result in substantial re-work impacts. The comparison of modeling algorithms is further complicated since many of the owners of the programs may be reluctant to provide detailed descriptions of their commercial products – a situation analogous to requesting source code from Microsoft for their word processing programs. The customer must be clear on what their expectations are when it comes to the verification process. In summary, the approach that appears best initially carries with it significant risks to both the signal system supplier responsible for block design verification and the customer. The supplier’s schedules and budgets are subject to potentially severe impacts, resulting in difficulties with timely delivery of an operational control system to the customer. These risks can be reduced, if not fully eliminated, by careful planning at the early stages of the project. With a clear definition from the customer of the responsibilities and requirements for the block design verification process, the signal system supplier can more accurately estimate the time and budget necessary to meet the customer’s needs, and is much less likely to encounter unexpected delays and cost overruns once the project is awarded. Equally important is the investment of time up front to prepare a comprehensive package that includes all of the input data required to perform block design, and to provide these data to both the initial developer and the signal system supplier responsible for the verification process. Attention to these two items would serve to get any project that involves block design verification off to a good start. President's Column continued from page 11 for operators, designers, car builders, regulators, freight railroads, passenger railroads and other agencies to meet to develop long-lasting and comprehensive design principles that can be used to guide the industry over the decades ahead as this issue is resolved and implemented. We encourage all passenger railroads and rail transit agencies to have their voices heard in this ever-changing arena by recommending staff to join and participate in AREMA and its Passenger & Transit Functional Group. Thanks for your report, Mark. Next month, John Unsworth, manager, structures planning & design for Canadian Pacific Railway and vice president of the Structures Functional Group, will report on that Group’s activities. The selection process for the tenth Dr. W. W. Hay Award of Excellence has begun and this year’s chair, Mike Franke, has issued a call for entries. The award was established by the directors of AREMA to recognize outstanding achievement in railway engineering and to honor the memory and accomplishments of one of their members and leaders: William Walter Hay, a professional railroader, consultant and Professor of Railway Civil Engineering at the University of Illinois. The purpose of the award is to honor innovative railway engineering procedures, projects and products and the individual(s) who have created and successfully applied them to the railroad industry. Entries should be received at AREMA HQ no later than June 15, 2008. Check the AREMA Website, www.arema.org, for more details. Have a safe and productive day. - Larry Etherton Railway Track & Structures April 2008 17 http://www.arema.org http://www.rtands.com

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Railway Track & Structures - April 2008 Contents On Track Industry Today Supplier News AREMA News NRC News TTCI R&D Railroads Seeking More Advanced Systems to Handle Materials SKOL Bounces Back From Summer Flood Landmark Railroad Bridges Need Inspection, Too Products and Literature People Calendar Sales Representatives Advertisers Index Website Directory Professional Directory Classified Advertising Chicago Perspective

Railway Track & Structures - April 2008

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