Question: Could you please provide references, if available, which discusses current technologies used by DOT for rail inspection.
Answer: First, as to the wording in the Question: "used by DOT for rail inspection",DOT does not normally inspect rail itself, rather, FRA safety regulations require operating railroads to conduct internal rail flaw inspections. These are commonly done through a contractor possessing this specialized equipment.
Regarding resources on inspection techniques, a great deal of material has been published over the years. I suggest starting with the following report available on the internet at this site: http://www.mountain-plains.org/MPC_HTML_DOC/MPC99-106.htm and then, conducting an internet search using terms similar to "rail flaw inspection technology".
Question: What is the intended application for this device?
Answer: To detect large transverse rail defects.
Question: Will it be used on all classes of track?
Answer: If the railroads choose to do so.
Question: Who will be the end user?
Answer: Could be the railroads or contractors.
Question: Will it be used for full 8 or more hour shifts or short inspection runs?
Answer: Probably both.
Question: Will it be used at night or in the absence of light?
Answer: It should be capable of operating at night.
Question: Must this system be designed for setup and take down by one person? Two?
Answer: One person should be able to set up system, easily.
Question: Provide more information/description on the minimum defect size. Will a transverse hair line crack, one inch deep have to be detected? Or only cracks which have opened to be a one inch longitudinal gap of much shorter depth?
Answer: Transverse defects of most immediate concern are somewhat oval in shape, with an edge either near the rail head surface (either the running surface or gage face) or only nearer the center of the rail head.
Question: Do you have pictures of the rail anomalies that you wish detected? Or references to publicly available reports?
Answer: Regarding resources on inspection techniques and defects, a great deal of material has been published over the years. I suggest starting with the following report available on the internet at this site: http://www.mountain-plains.org/MPC_HTML_DOC/MPC99-106.htm and then, conducting an internet search using terms similar to "rail flaw inspection technology".
Question: Will the system be required to detect defects on the rail web or just the head?
Answer: The minimum requirement is to detect in the rail head. Ability to detect in the web as well, is even better.
Question: What are expectations on calibration and detector head cleaning frequency?
Answer: Calibration should be simple and required to be done, or checked, no more than once a day - at the start of inspection. Any cleaning required should be able to be done, also, at the beginning of the inspection day.
Question: Will the FRA supply a test vehicle and/or test location that can be used during development?
Answer: The FRA will not supply a test vehicle or test location. The FRA would be willing to help the developer find a test location, but test expenses would be the responsibility of the developer.
Question: FRA rules require that any indication considered suspect by the test equipment on the test car be hand verified immediately. Should the proposed system include provisions for a hand-held device? If the answer is yes, then, technically, the system scanning speed would be impacted by the time it takes to stop the moving rail vehicle, make the hand held measurement and then resume scanning. Would this stop-start scenario be an issue?
Answer: The SBIR requirement does not include hand testing verification.
Question: There are several rail inspection systems currently available commercially. These systems do not meet the solicitation's packaging size requirement, and likely the cost requirement. Of all of the possible performance improvements that an innovative system could provide (size, cost, inspection speed, inspection resolution, defect size detection, performance under adverse conditions), which are the improvements that the FRA would most like to implement, and which are not as important? For example, cost can be reduced by sacrificing inspection resolution or speed by using less expensive transducers.
Answer: The intent is to meet the requirements stated in the SBIR announcement.
Question: Would you please quantify the extent to which false positive indications must be minimized? Numerically, how rare should missed defects be?
Answer: No exact number can be given, but conceptually, the idea is that false positive indications should be a small percentage of all indications.
Question: Are the statistical requirements of question #3 constant for all inspection speeds? This question is motivated by the notion that there may be a trade off between scanning speed and measurement accuracy.
Answer: As long as false positive indications are infrequent, performance may vary at different speeds, as long as detection performance remains acceptable.
Question: Is there a preference on the part of the FRA for one scanning technology versus another (e.g., acoustical, eddy current, or infrared)? Thank you in advance for your attention to this request.
Answer: No preference for any particular method.
Question: I am currently preparing a SBIR proposal in response to SBIR 02-FR1, and have a question. The main objective is to construct an instrument for identification of defects in rail. Would the DOT able to supply rail with known/quantified defects for testing such equipment? If not, whom would you suggest we contact to do so? We can simulate defective material if necessary, but would prefer to avoid this. Thank you.
Answer: DOT does not supply rail defect samples. Developers of rail defect detection technology can demonstrate its performance through testing at the Transportation Technology Center near Pueblo Colorado. Testing would be done at developer's expense.
Question: Are pictures of rail defects available?
Answer: In general, a great deal of material on inspection techniques has been published over the years. I suggest starting with the following report available on the internet at this site: http://www.mountain-plains.org/MPC_HTML_DOC/MPC99-106.html and then, conducting an internet search using terms similar to "rail flaw inspection technology". Some pictures of internal rail defects are in the report at the above-listed web site.
Question: Can rail defects be distinguished from normal splices?
Answer: Any technique which could not clearly distinguish between a normal rail joint and an internal defect would not be usable.
Question: Will the system be operated only in daylight, or must it also operate in the dark?
Answer: The desired system must operate at night as well as it does during daylight.
Question: Are defects always recognizable in visible light, or is a process like X-Ray required?
Answer: Externally visible signs of internal rail defects are typically not present until the defect has reached extreme (near-break) dimensions.
Question: Is an audible indication of a defect the only required indication, or is it also necessary to display or record coordinates such as GPS location?
Answer: GPS location would be considered a plus. The basic requirement is to provide a clear indication (an alarm) to the operator at the time a defect is detected, using sound, lights, or other obvious means.
Question: Are approximate dimensions of the inspection truck and rail available?
Answer: See report in the above-listed web site.
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