145:
176:. A more recent, and probably better, technique is to lift the rails and ties, and to force stones, smaller than the track ballast particles and all of the same size, into the gap. That has the advantage of not disturbing the well-compacted ballast on the trackbed, which tamping is likely to do. The technique is called pneumatic ballast injection (PBI), or, less formally, "stoneblowing". However, it is not as effective as fresh ballast, because the smaller stones tend to move down between the larger pieces of ballast and degrade its bonds.
52:
40:
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185:
with the density of rail traffic, as faster and heavier traffic requires greater stability. The quantity of ballast also tends to increase over the years as more and more ballast is piled onto an existing roadbed. Some figures from an 1897 report listing requirements for light railways (usually narrower than standard gauge) are:
133:, and in unfavourable conditions, overloading the soil causes the track to sink, usually unevenly. Ballast less than 300 mm (12 inches) thick can lead to vibrations that damage nearby structures. However, increasing the depth beyond 300 mm (12 inches) confers no extra benefit in reducing vibration.
168:
Regular inspection of the ballast shoulder is important. The shoulder acquires some amount of stability over time, being compacted by traffic, but maintenance tasks such as replacing ties, tamping, and ballast cleaning can upset that stability. After performing those tasks, it is necessary either for
160:
The dump and jack method cannot be used through tunnels, under bridges, or where there are platforms. Where the track is laid over a swamp the ballast is likely to sink continuously, and needs to be "topped up" to maintain its line and level. After 150 years of topping up at Hexham, Australia, there
136:
In turn, track ballast typically rests on a layer of sub-ballast, small crushed stones which provide a solid support for the top ballast and reduce ingress of water from the underlying ground. Sometimes an elastic mat is placed between the sub-ballast and ballast, significantly reducing vibration.
184:
The quantity of ballast used tends to vary with gauge, with the wider gauges tending to have wider formations, although one report states that for a given load and speed, narrowing the gauge only slightly reduces the quantity of earthwork and ballast needed. The depth of ballast also tends to vary
129:, the amount of traffic on the line, and various other factors. Track ballast should never be laid down less than 150 mm (6 inches) thick, and high-speed railway lines may require ballast up to 0.5 metres (20 inches) thick. An insufficient depth of ballast causes overloading of the underlying
140:
It is essential for ballast to both cover the ties and form a substantial "shoulder" to restrain lateral movement of the track. This shoulder should be at least 150 mm (6 inches) wide, and may be as wide as 450 mm (18 inches). Most railways use between 300 and 400 mm (12 and 16
152:
Stones must be irregular, with sharp edges to ensure they properly interlock with each other and the ties to fully secure them against movement. Speed limits are often reduced for a period of time on sections of track where fresh ballast has been laid in order to allow it to properly settle.
156:
Ballast can only be cleaned so often before it is damaged beyond re-use. Ballast that is completely fouled can not be corrected by shoulder cleaning. One method of "replacing" ballast is to simply dump fresh ballast on the track, jack the whole track on top of it, and then tamp it down.
431:
or concrete ties. A 450 mm (18 in) shoulder significantly increases lateral stability and reduces required maintenance, though little or no resistance to buckling is gained above this size. See
82:
that can compromise the integrity of the combined track structure. Ballast also physically holds the track in place as the trains roll over it. Not all types of railway tracks use ballast.
70:(UK: sleepers) are laid. It is packed between, below, and around the ties. It is used to bear the compression load of the railroad ties, rails, and
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896:
749:
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172:
If the trackbed becomes uneven, it is necessary to pack ballast underneath sunken ties to level the track again, which is usually done by a
157:
Alternatively, the ballast underneath the track can be removed with an undercutter, which does not require removing or lifting the track.
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trains to run at reduced speed on the repaired sections, or to employ machinery to compact the shoulder again.
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150 mm (6 inches) is with 300 mm (12 inches) recommended for use in heavy traffic, or with
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second class line – 41.5 lb/yd (20.6 kg/m) rail – 1,135 cu yd/mi (539 m/km).
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1013:
777:
International
Federation for Structural Concrete (fédération internationale du béton) bulletin #37.
1349:
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256:
215:
third class line – 30 lb/yd (14.9 kg/m) rail – 600 cu yd/mi (290 m/km).
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The appropriate thickness of a layer of track ballast depends on the size and spacing of the
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614:
Anderson, W. F.; Key, A. J. (1999). "Two layer ballast beds as railway track foundations".
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1186:
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1028:
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126:
93:, bank run (unwashed) gravel, torpedo gravel (a mixture of coarse sand and small gravel),
616:
Twelfth
European Conference on Soil Mechanics and Geotechnical Engineering (Proceedings)
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Railway
Maintenance Equipment: The Men and Machines that Keep the Railroads Running
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appears to be 10 m (33 ft) of sunken ballast under the tracks.
75:
63:
114:
874:
117:" comes from a nautical term for the stones used to stabilize a ship.
1191:
90:
506:
227:
55:
Track ballast supports railway sleepers, which carry railway track.
143:
102:
85:
A variety of materials have been used as track ballast, including
50:
38:
198:
130:
110:
106:
94:
878:
322:
American
Railway Engineering and Maintenance-of-Way Association
47:. The sharp edges help the particles interlock with each other.
590:. National Library of Australia. 29 September 1897. p. 5
363:
361:
359:
285:
283:
281:
279:
277:
635:
Vibration
Problems in Structures: Practical Guidelines
148:
Ballast must be irregularly shaped to work properly.
1342:
1260:
1155:
1001:
913:
189:first class line – 60 lb/yd (29.8 kg/m)
800:Selig, Ernest Theodore; Waters, John M. (1994).
704:Ellis' British Railway Engineering Encyclopaedia
802:Track Geotechnology and Substructure Management
744:. Leiden, The Netherlands: CRC Press/Balkema.
890:
402:
400:
8:
742:Advanced rail geotechnology--ballasted track
453:Train Wreck: The Forensics of Rail Disasters
547:
897:
883:
875:
562:, p. 265, Pneumatic Ballast Injection
378:
376:
27:Trackbed upon which railway ties are laid
479:
477:
759:Institution of Civil Engineers (1988).
492:
367:
289:
273:
870:Photos of ballast regulators in the UK
783:Handbook of Transportation Engineering
342:Beyer, S. W.; Williams, I. A. (1904).
315:"Selection and Maintenance of Ballast"
43:Good quality track ballast is made of
761:Urban Railways and the Civil Engineer
559:
7:
865:Photos of ballast cleaners in the UK
654:Engineering Geology and Construction
633:Bachmann, Hugo; et al. (1997).
535:
437:
433:
415:
391:
847:New South Wales: Ballast 1850-1987
348:. pp. 534–537. Archived from
165:in the United Kingdom is similar.
25:
226:
62:is the material which forms the
507:"Railway Materials Case Study"
458:Johns Hopkins University Press
1:
740:Indraratna, Buddhima (2011).
673:Practical Railway Engineering
671:Bonnett, Clifford F. (2005).
721:Hay, William Walter (1982).
675:(2nd ed.). London, UK:
1421:
1105:Transfer table (traverser)
854:, December, 2004 pp443–462
852:Australian Railway History
823:. MBI Publishing Company.
29:
1093:ground-level power supply
548:Anderson & Key (1999)
32:Ballast (disambiguation)
1078:Railway electrification
819:Solomon, Brian (2001).
725:. John Wiley and Sons.
313:Kellogg, H. W. (1946).
174:ballast tamping machine
677:Imperial College Press
450:Bibel, George (2012).
429:continuous welded rail
406:Bachmann 1997, p. 121.
149:
56:
48:
1395:Aggregate (composite)
1217:Platform screen doors
302:Tubular Modular Track
147:
54:
42:
1167:Anti-trespass panels
723:Railroad Engineering
702:Ellis, Iain (2006).
587:The Brisbane Courier
483:Solomon 2001, p. 43.
436:, pp. 407–408;
345:The Geology of Clays
30:For other uses, see
1405:Rail infrastructure
1014:Classification yard
781:Kutz, Myer (2004).
652:Bell, F.G. (2004).
460:. pp. 287–88.
1273:Motive power depot
1227:Signalling control
804:. Thomas Telford.
763:. Thomas Telford.
440:, Section 24.4.2.
382:Bell 2004, p. 396.
352:on 13 August 2010.
257:Maintenance of way
150:
57:
49:
1382:
1381:
1100:Railway turntable
921:
751:978-0-203-81577-9
686:978-1-86094-515-1
538:, Section 24.4.2.
526:Hay 1982, p. 408.
456:. Baltimore, MD:
262:Track maintenance
242:Ballastless track
16:(Redirected from
1412:
1277:Railway workshop
993:Transition curve
963:Fastening system
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582:"LIGHT RAILWAYS"
578:
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571:IFSC #37, ch. 9.
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1232:Structure gauge
1187:Defect detector
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953:Clip and scotch
943:Breather switch
909:
903:
861:
850:Longworth, Jim
842:
840:Further reading
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785:. McGraw-Hill.
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656:. Spon Press.
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637:. Birkhäuser.
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618:. AA Balkema.
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770:0-7277-1337-X
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234:Trains portal
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87:crushed stone
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72:rolling stock
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68:railroad ties
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61:
60:Track ballast
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46:
45:crushed stone
41:
37:
33:
19:
1252:Wayside horn
1202:Interlocking
1182:Catch points
1142:Water trough
1044:Passing loop
1024:Pocket track
1009:Balloon loop
973:Ladder track
932:
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845:
820:
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782:
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741:
722:
706:. Lulu.com.
703:
672:
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592:. Retrieved
585:
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560:Ellis (2006)
555:
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531:
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510:. Retrieved
500:
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445:
423:
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350:the original
344:
337:
325:. Retrieved
321:
308:
297:
252:Gandy dancer
183:
171:
167:
159:
155:
151:
139:
135:
124:
121:Construction
113:. The term "
109:, and burnt
103:coal cinders
84:
59:
58:
36:
1177:Buffer stop
1137:Water crane
1049:Track gauge
988:Tie/Sleeper
536:Kutz (2004)
66:upon which
1389:Categories
1350:Industrial
1334:Water stop
1295:for trains
1287:Roundhouse
1261:Structures
1247:Train stop
1197:Guard rail
1172:Block post
1160:and safety
1157:Signalling
1088:third rail
1061:Rail track
1054:dual gauge
938:Baulk road
607:References
416:Hay (1982)
392:Hay (1982)
201:(810
195:cu yd
180:Quantities
141:inches).
80:vegetation
18:Ballasting
1300:for goods
1242:Tell-tale
1073:Rail yard
1039:Guide bar
1019:Headshunt
1002:Trackwork
968:Fishplate
958:Date nail
919:(history)
695:443641662
438:Kutz 2004
268:Footnotes
163:Chat Moss
89:, washed
1355:Military
1312:building
1282:Platform
1192:Derailer
1110:Roll way
1029:Junction
928:Axe ties
512:4 August
434:Hay 1982
327:27 March
220:See also
76:drainage
64:trackbed
1365:station
1360:Private
1307:Station
983:Profile
933:Ballast
115:ballast
1127:Switch
1115:Siding
915:Tracks
827:
808:
789:
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748:
729:
710:
693:
683:
660:
641:
622:
594:21 May
464:
91:gravel
1343:Types
1322:ghost
1317:clock
1291:Shed
905:Rail
318:(PDF)
99:chats
1370:list
1327:list
948:Cant
825:ISBN
806:ISBN
787:ISBN
765:ISBN
746:ISBN
727:ISBN
708:ISBN
691:OCLC
681:ISBN
658:ISBN
639:ISBN
620:ISBN
596:2011
514:2016
462:ISBN
329:2021
191:rail
131:soil
127:ties
111:clay
107:sand
95:slag
1147:Wye
1391::
689:.
679:.
584:.
476:^
399:^
375:^
358:^
320:.
276:^
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207:km
199:mi
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101:,
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795:.
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735:.
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