312:. Poor ventilation in long or narrow tunnels can starve the locomotive of power. The solution is analogous to compensation for curvature and requires the gradient in the tunnel and for some distance on either side to be greatly reduced compared to the ruling grade. Unfortunately, the necessary compensation for gradient is not a simple equation, but is rather a trial and error process. Since one cannot build several tunnels to find out which one is best, it is useful to study existing tunnels with steep gradients.
375:, Congress set the Standard Grade for railroads eligible for subsidies and grants in the 1850s. They took as that standard the one adopted by the Cumberland – Wheeling Railway, that grade being 116 feet per mile (22.0 m/km) or 2.2%. Later when charters were drawn up for the Canadian Pacific Railway in Canada and for the Union Pacific Railroad, the national governments imposed the Standard Ruling Grade on the two lines because each received federal assistance and regulation. (Vance, JE Jr.,1995)
262:(or how light the train) must be in order for the run to be made without assistance. Even if 99% of the line could be run with a low-powered (and inexpensive) locomotive, if at some point on the line there is a steeper gradient than such train would be able to climb, this gradient "rules" that a more powerful locomotive must be used, in spite of it being far too powerful for the rest of the line. This is why special "
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issue is whether a running start should be assumed and, if yes, the speed to assume. Another issue is the train length to assume, given that certain lengths exceed the length of the hill in question. And if a running start at some arbitrary speed is assumed, the calculated "ruling grade" will be different for locomotives having different power-vs-speed characteristics.
266:" (also dubbed "Bankers") are often stationed near steep grades on otherwise mild tracks. It is cheaper than running a too-powerful locomotive over the entire track mileage just in order to make the grade, especially when multiple trains run over the line each day (to help justify the fixed daily cost of the helper operation).
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face nothing steeper than 0.5% on Track 1, the traditional westward track, but nowadays they might need to approach the
Benicia bridge on Track 2, which includes 0.7 miles at about 1.9% on otherwise near-level track. Using this as an example, several issues arise on defining "ruling grade". One
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William H. Hay says "The ruling grade may be defined as the maximum gradient over which a tonnage train can be hauled with one locomotive....The ruling grade does not necessarily have the maximum gradient on the division. Momentum grades, pusher grades, or those that must regularly be doubled by
286:) wagons – try to follow the chord of the curve and not the arc. To compensate for this, the gradient should be a little less steep the sharper the curve is; the necessary grade reduction is assumed to be given by a simple formula such as 0.04 per cent per "degree of curve", the latter being a
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at Wells; the "ruling grade" from Sparks to Ogden could be considered 0.43%. But nowadays the railroad doesn't base helper engines at Wells so trains must leave Sparks with enough power to climb the 1.4%, making that the division's ruling grade.
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As such, the term can be ambiguous; and is even more ambiguous if the ruling grade is impacted by the effect of a momentum grade. Overland Route trains from
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used in the United States. On a 10-degree curve (radius 573.7 feet) the grade would thus need to be 0.4% less than the grade on straight track.
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A ruling grade is often found at a long climb up to a summit. Ideally, the cutting at the summit should be as deep as possible, such as at
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Other things being equal, a train is harder to pull around a curve than it is on straight track because the wagons – especially bogie (2
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tonnage trains may be heavier." This means the "ruling grade" may change if the management chooses to operate the railroad differently.
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is usually used as a synonym for "steepest climb" between two points on a railroad. More simply, the steepest
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1 in 100 – 1.00% ; (1 in 131 average) – 1874 – fume problems
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faced nothing steeper than 0.43% in the 531 miles from
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494:List of steepest gradients on adhesion railways
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435:1 in 50 – 2.00% - on other side of summit to
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429:1 in 49 – 2.04% - asphyxiation death in 1942
504:Old Main Line (Baltimore and Ohio Railroad)
61:Learn how and when to remove these messages
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407:lines, and non-operational country lines.
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220:Learn how and when to remove this message
158:Learn how and when to remove this message
343:—except for a few miles of 1.4% east of
258:to be climbed dictates how powerful the
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450:1 in 100 – 1.00% - 1839 – double track
351:with a 5500-ton train) and would get
294:Compensation for gradients in tunnels
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472:1 in 201 – 0.50% - 1845 – twin bores
96:adding citations to reliable sources
319:General situation in North America
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466:when built – ventilation problems
401:Australian Rail Track Corporation
42:This article has multiple issues.
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83:needs additional citations for
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200:the claims made and adding
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462:1 in 105 – 0.95% - 1916 –
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288:measure of curve sharpness
278:Compensation for curvature
707:Switch / turnout / points
697:Grand circle / roundabout
533:December 8, 2008, at the
395:Curve and Gradient Books
417:(in order of steepness)
327:trains eastward across
269:In the 1953 edition of
489:Hillclimbing (railway)
444:1 in 90 – 1.11% - 1865
361:Sacramento, California
300:Table of turn tunnels
843:Minimum curve radius
810:Zig Zag / Switchback
92:improve this article
782:Interchange station
687:Facing and trailing
654:Classification yard
271:Railway Engineering
712:Swingnose crossing
310:diesel locomotives
185:possibly contains
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639:Pocket track
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601:Double track
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509:Rack railway
464:double track
423:1 in 33 – 3%
421:Otira Tunnel
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90:Please help
85:verification
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18:Ruling grade
833:Track gauge
692:Grand union
403:– excludes
148:August 2012
516:References
448:Box Tunnel
298:See also:
194:improve it
118:newspapers
47:improve it
664:Junctions
649:Rail yard
634:Headshunt
611:Crossover
250:The term
210:July 2018
198:verifying
53:talk page
868:Category
727:Stations
531:Archived
477:See also
574:Railway
389:Ardglen
379:Summits
371:In the
365:Oakland
192:Please
132:scholar
815:Spiral
745:Island
349:2-10-2
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329:Nevada
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345:Wells
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139:JSTOR
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848:Cant
750:Side
385:Shap
333:Utah
331:and
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111:news
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