301:. 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.
364:, 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)
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251:(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.
255:" (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
275:) 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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Moisture from exhausts and springs can also make the rails slippery, and allowance may need to be taken for that as well.
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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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483:List of steepest gradients on adhesion railways
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424:1 in 50 – 2.00% - on other side of summit to
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418:1 in 49 – 2.04% - asphyxiation death in 1942
493:Old Main Line (Baltimore and Ohio Railroad)
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50:Learn how and when to remove these messages
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396:lines, and non-operational country lines.
227:Learn how and when to remove this message
209:Learn how and when to remove this message
147:Learn how and when to remove this message
332:—except for a few miles of 1.4% east of
247:to be climbed dictates how powerful the
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439:1 in 100 – 1.00% - 1839 – double track
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340:with a 5500-ton train) and would get
283:Compensation for gradients in tunnels
461:1 in 201 – 0.50% - 1845 – twin bores
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85:adding citations to reliable sources
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308:General situation in North America
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455:when built – ventilation problems
390:Australian Rail Track Corporation
31:This article has multiple issues.
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72:needs additional citations for
39:or discuss these issues on the
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394:Transport Asset Holding Entity
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189:the claims made and adding
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766:Cross-platform interchange
451:1 in 105 – 0.95% - 1916 –
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277:measure of curve sharpness
267:Compensation for curvature
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696:Switch / turnout / points
686:Grand circle / roundabout
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522:December 8, 2008, at the
384:Curve and Gradient Books
406:(in order of steepness)
316:trains eastward across
258:In the 1953 edition of
478:Hillclimbing (railway)
433:1 in 90 – 1.11% - 1865
350:Sacramento, California
289:Table of turn tunnels
832:Minimum curve radius
799:Zig Zag / Switchback
81:improve this article
771:Interchange station
676:Facing and trailing
643:Classification yard
260:Railway Engineering
701:Swingnose crossing
299:diesel locomotives
174:possibly contains
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443:Combe Down Tunnel
431:Dove Holes Tunnel
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422:Devonshire Tunnel
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618:Balloon loop
610:Rail sidings
590:Double track
585:Passing loop
580:Single track
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498:Rack railway
453:double track
412:1 in 33 – 3%
410:Otira Tunnel
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79:Please help
74:verification
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822:Track gauge
681:Grand union
392:– excludes
137:August 2012
505:References
437:Box Tunnel
287:See also:
183:improve it
107:newspapers
36:improve it
653:Junctions
638:Rail yard
623:Headshunt
600:Crossover
239:The term
199:July 2018
187:verifying
42:talk page
857:Category
716:Stations
520:Archived
466:See also
563:Railway
378:Ardglen
368:Summits
360:In the
354:Oakland
181:Please
121:scholar
804:Spiral
734:Island
338:2-10-2
326:Sparks
318:Nevada
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334:Wells
330:Ogden
245:grade
128:JSTOR
114:books
837:Cant
739:Side
374:Shap
322:Utah
320:and
297:and
273:axle
100:news
729:Bay
691:Wye
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