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24-557: The Satpura Railway was a 2 ft 6 in ( 762 mm ) narrow-gauge railway in the states of Madhya Pradesh and Maharashtra in central India. After the Great Famine of 1876–78 in central India, the Bengal Nagpur Railway began planning to open a low-cost railway track that would unite the region, allowing both access to the agricultural and mineral resources of the region, further safeguarding

48-518: A normal distribution , the tails of measured values may extend well beyond plus and minus three standard deviations from the process average. Appreciable portions of one (or both) tails might extend beyond the specified tolerance. The process capability of systems, materials, and products needs to be compatible with the specified engineering tolerances. Process controls must be in place and an effective quality management system , such as Total Quality Management , needs to keep actual production within

72-529: A clearance fit of somewhere between 0.04 mm (largest shaft paired with the smallest hole, called the Maximum Material Condition - MMC) and 0.112 mm (smallest shaft paired with the largest hole, Least Material Condition - LMC). In this case the size of the tolerance range for both the shaft and hole is chosen to be the same (0.036 mm), meaning that both components have the same International Tolerance grade but this need not be

96-460: A number. For example: H7 (hole, tapped hole , or nut ) and h7 (shaft or bolt). H7/h6 is a very common standard tolerance which gives a tight fit. The tolerances work in such a way that for a hole H7 means that the hole should be made slightly larger than the base dimension (in this case for an ISO fit 10+0.015−0, meaning that it may be up to 0.015 mm larger than the base dimension, and 0 mm smaller). The actual amount bigger/smaller depends on

120-426: A shaft with a nominal diameter of 10   mm is to have a sliding fit within a hole, the shaft might be specified with a tolerance range from 9.964 to 10 mm (i.e., a zero fundamental deviation, but a lower deviation of 0.036 mm) and the hole might be specified with a tolerance range from 10.04 mm to 10.076 mm (0.04 mm fundamental deviation and 0.076 mm upper deviation). This would provide

144-403: A specified temperature range, over a specified lifetime, and so on. Many commercially available resistors and capacitors of standard types, and some small inductors , are often marked with coloured bands to indicate their value and the tolerance. High-precision components of non-standard values may have numerical information printed on them. Low tolerance means only a small deviation from

168-442: Is also extremely useful: It indicates the frequency (or probability) of parts properly fitting together. An electrical specification might call for a resistor with a nominal value of 100 Ω ( ohms ), but will also state a tolerance such as "±1%". This means that any resistor with a value in the range 99–101   Ω is acceptable. For critical components, one might specify that the actual resistance must remain within tolerance within

192-409: Is analogous to "goal posts" in a football game : It implies that all data within those tolerances are equally acceptable. The alternative is that the best product has a measurement which is precisely on target. There is an increasing loss which is a function of the deviation or variability from the target value of any design parameter. The greater the deviation from target, the greater is the loss. This

216-617: Is described as the Taguchi loss function or quality loss function , and it is the key principle of an alternative system called inertial tolerancing . Research and development work conducted by M. Pillet and colleagues at the Savoy University has resulted in industry-specific adoption. Recently the publishing of the French standard NFX 04-008 has allowed further consideration by the manufacturing community. Dimensional tolerance

240-441: Is not a usable part according to the design intent. Tolerances can be applied to any dimension. The commonly used terms are: This is identical to the upper deviation for shafts and the lower deviation for holes. If the fundamental deviation is greater than zero, the bolt will always be smaller than the basic size and he hole will always be wider. Fundamental deviation is a form of allowance , rather than tolerance. For example, if

264-422: Is related to, but different from fit in mechanical engineering, which is a designed-in clearance or interference between two parts. Tolerances are assigned to parts for manufacturing purposes, as boundaries for acceptable build. No machine can hold dimensions precisely to the nominal value, so there must be acceptable degrees of variation. If a part is manufactured, but has dimensions that are out of tolerance, it

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288-526: The Nainpur – Mandla Fort line in 1909. The extensive network of 2 ft 6 in ( 762 mm ) gauge tracks measured just over 1,000 km. The Satpura Railway is fully made into 1,676 mm ( 5 ft 6 in ) broad gauge . The alignment follows the old 762 mm ( 2 ft 6 in ) narrow gauge line in most of the route excepting the hilly regions. Amla - Chhindwara - Nainpur - Mandla Fort section fully follows

312-601: The base dimension. For a shaft of the same size, h6 would mean 10+0−0.009, which means the shaft may be as small as 0.009 mm smaller than the base dimension and 0 mm larger. This method of standard tolerances is also known as Limits and Fits and can be found in ISO 286-1:2010 (Link to ISO catalog) . The table below summarises the International Tolerance (IT) grades and the general applications of these grades: An analysis of fit by statistical interference

336-424: The case in general. When no other tolerances are provided, the machining industry uses the following standard tolerances : When designing mechanical components, a system of standardized tolerances called International Tolerance grades are often used. The standard (size) tolerances are divided into two categories: hole and shaft. They are labelled with a letter (capitals for holes and lowercase for shafts) and

360-403: The components given value, when new, under normal operating conditions and at room temperature. Higher tolerance means the component will have a wider range of possible values. The terms are often confused but sometimes a difference is maintained. See Allowance (engineering) § Confounding of the engineering concepts of allowance and tolerance . In civil engineering , clearance refers to

384-653: The desired tolerances. A process capability index is used to indicate the relationship between tolerances and actual measured production. The choice of tolerances is also affected by the intended statistical sampling plan and its characteristics such as the Acceptable Quality Level. This relates to the question of whether tolerances must be extremely rigid (high confidence in 100% conformance) or whether some small percentage of being out-of-tolerance may sometimes be acceptable. Genichi Taguchi and others have suggested that traditional two-sided tolerancing

408-401: The difference between the loading gauge and the structure gauge in the case of railroad cars or trams , or the difference between the size of any vehicle and the width/height of doors, the width/height of an overpass or the diameter of a tunnel as well as the air draft under a bridge , the width of a lock or diameter of a tunnel in the case of watercraft . In addition there is

432-438: The effects of tolerances: Design of experiments , formal engineering evaluations, etc. A good set of engineering tolerances in a specification , by itself, does not imply that compliance with those tolerances will be achieved. Actual production of any product (or operation of any system) involves some inherent variation of input and output. Measurement error and statistical uncertainty are also present in all measurements. With

456-508: The inhabitants should another famine arise. Nainpur was the focal point of the network and was even bestowed with the prestige of being a divisional headquarters for some time. The lines came up in the early years of the 20th century. The first portion of the Gondia – Nainpur line was opened on 13 April 1903, Nainpur and Chhindwara were connected in 1904 and Jabalpur in 1905. The Chhindwara – Pench Coalfield line came up in 1906 to 07 and

480-648: The old 762 mm ( 2 ft 6 in ) narrow gauge alignment. But Jabalpur - Nainpur - Balaghat - Gondia section has different alignment in some parts. The section between Gondia and Balaghat was converted to broad gauge in 2005 and 2006 connecting Balaghat to India's national network for the first time. Work was completed on converting the Balaghat – Nainpur - Jabalpur section to broad gauge in 2021. The narrow-gauge trains running between Jabalpur and Balaghat were stopped in October 2015 and

504-423: The tolerance (for example, a temperature that is too hot or too cold) is said to be noncompliant, rejected, or exceeding the tolerance. A primary concern is to determine how wide the tolerances may be without affecting other factors or the outcome of a process. This can be by the use of scientific principles, engineering knowledge, and professional experience. Experimental investigation is very useful to investigate

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528-474: The track was closed for gauge conversion. The 85.1 kilometres (52.9 mi) broad-gauge track from Jabalpur to Ghunsore railway station was opened in September 2017 and the 35.1 kilometres (21.8 mi) track from Ghunsore to Nainpur opened in 2018. The last work of 75.5 kilometres (46.9 mi) between Nainpur to Balaghat was expected to be operational in mid-2020, but due to COVID-19 pandemic it

552-578: Was delayed, while also converted into an electrified line for increased average speed. After that, it was started on 8 March 2021. The 183 kilometres (114 mi) long Chhindwara - Nainpur - Mandla Fort section is nearing completion with crs inspection happened on 24th of february 2023. Nainpur - Mandla Fort section being operational since 15 March 2021. 2 ft 6 in gauge railways 2 ft 6 in ( 762 mm ) gauge railways are narrow gauge railways with track gauge of 2 ft 6 in ( 762 mm ). This type of rail

576-642: Was promoted especially in the colonies of the British Empire during the second half of the nineteenth century by Thomas Hall and Everard Calthrop . Several Bosnian-gauge railways with 760 mm ( 2 ft  5 + 15 ⁄ 16  in ) are found in south-eastern Europe. 760 mm (29.92 in) is well within tolerances of 762 mm (30.00 in). Engineering tolerance Dimensions, properties, or conditions may have some variation without significantly affecting functioning of systems, machines, structures, etc. A variation beyond

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