22:
431:
535:'s method of preventing slippery rail is the Gel Trains. These three trains spray a high-pressure mixture of Sandite on the rails; in the fall, the Gel Trains also clean the rails using the high-pressure water jet method ahead of the gel application. These trains consist of a pressure washer and gel dispenser mounted on a converted flatcar, and a tank car which carries water. They are pulled on one end by one of SEPTA's work diesels (or a diesel borrowed from a local shortline such as the
267:
218:
278:
Treatment measures generally involve some system to jet or blast the accumulated deposit away, or to coat it with a high-friction material. Blasting is usually carried out with water jets, often in combination with mechanical scrubbing apparatus. The coating method usually involves depositing sand in
242:
on the steel tyres, especially if the wheels are still sliding when arriving at a non-greasy section of rail, e.g. one that has previously been sanded. This causes the wheels to go out of profile (known colloquially as 'wheel flats'), which subsequently leads to severe vibration and the need for the
91:
and are then heavily compressed by trains into a slippery low-friction coating on the rail and on the wheel treads. If the climate is damp, the wet leaves adhere to the rail very effectively. The draft caused by the passage of the train causes nearby leaves to be caught up in air currents, and more
597:
after cutting back, and have large, flat leaves, which stick to the line and cause severe slippery rail. Other types of tree that cause problems are quick-growing, pioneering trees, or those producing a substantial amount of leaves. Poplars are particularly troubling because they tend to shed limbs.
558:
During autumn, a fleet of
Railhead Treatment Trains (RHTT) run across the network using high pressure water-jetting to clean the railhead. These trains are timetabled to run between scheduled daytime services as well as during the night when less rail activity can allow the railhead contamination to
525:
has used a similar method, which has proven effective. The device it uses is called "Aqua-Track" which, while attached to a moving rail car, sprays water at a pressure of 20,000 psi (140 MPa) on to the part of the rail where the leaves cling. Since this system was introduced in 2002, the
289:
Both of these processes are effective for a limited duration; the jetting method is ineffective as soon as the next leaf falls; the sand deposition method is more durable, although rainfall usually removes the deposited sand quickly. Another method is using a high voltage electrical spark or plasma
225:
The loss of friction between wheels and rail results in loss of tractive force: the wheels begin to spin, and in some instances the train is unable to move. In braking, substantial loss of friction results in reduced braking force. Braking distances are considerably longer, and in extreme cases the
412:
After receiving a report of low adhesion conditions, the signaller will contact drivers of following trains by radio to warn them. If it is safe to do so, the signaller may tell a driver to carry out a controlled test stop. That driver will then stop the train using the brake force appropriate to
362:
Before each leaf-fall season, train companies may arrange low-adhesion training for newly qualified drivers. This consists of taking over a section of line during a quiet period. Using lineside markers each driver gets their train up to speed and then makes a full service brake application under
152:
era, trees and other lineside vegetation would be regularly cut back to reduce the risk of their being ignited by sparks from the locomotive. As the railways ceased to use steam traction, this maintenance was allowed to lapse, and the resulting extra growth increases the supply of leaves thereby
145:. It was the duty of the fireman when necessary to dismount from the locomotive and gather track ballast to throw under the driving wheels to maintain grip, but in this particular instance dirty ballast, containing a proportion of earth, failed to achieve the required outcome.
408:
Drivers are required by the
Rulebook, to report to the signaller immediately either, any low railhead adhesion at a location not published in the Sectional Appendix, or any exceptionally poor rail adhesion at locations which are published in the Sectional
922:
108:
debris and creates a paste that separates the wheel and rail reducing adhesion. Although the effect is only short term, its unpredictability can cause a significant incident to occur. A morning dew can have the same effect.
370:
Although this provides only an approximation of how a train will behave during low adhesion, it does ensure that the driver can recognize the onset of wheel slide and will know the correct actions to take when it occurs.
103:
Even summer can have its problems. A light rain shower following a long period of dry weather can sometimes cause similar low adhesion conditions to those of leaf fall contamination. As the water dries it mixes with
329:("dry ice") which is fired at the track through a nozzle, removing commination through surface cooling, kinetic energy and sublimation. Other methods have been trialed include microwave plasma and ultrasound.
177:
in central
Victoria were also affected by a Portuguese millipede plague, causing several trains to be cancelled. The crushing of Portuguese millipedes is suspected to have caused a crash between two trains at
95:
Winter can provide problems of low adhesion when snow and ice are deposited on running lines. Just as with road vehicles, black ice can cause trains to encounter difficulty when starting away, or can initiate
279:
a paste on to the rail; as the sand may exacerbate the risk of unwanted insulation, the sand mix sometimes contains metal particles. The coating is applied from special trains (colloquially referred to as "
701:
Lewis, S.R.; Lewis, R.; Richards, P.; Buckley-Johnstone, L.E. (2014). "Investigation of the isolation and frictional properties of hydrophobic products on the rail head, when used to combat low adhesion".
286:
Lineside-fitted
Traction gel applicators which apply liquid to the railhead as a train passes are fitted at sites where significant low adhesion regularly occurs, such as on the approach to stations.
359:
or 'over-running' a station. At these times, train drivers adopt 'defensive driving', which involves braking earlier and more gently than usual. Also, less power is applied when starting trains.
1586:
1554:
621:
gel on the tracks. In autumn 2016, nearly 90,000 litres (24,000 US gal) of this gel was applied on the Dutch railway network. In the fall of 2014 a pilot, in collaboration with
1362:
740:
Principles and
Applications of Tribology: Pergamon International Library of Science, Technology, Engineering and Social Studies: International Series in Materials Science and Technology
824:
343:
Wheel slide protection (WSP) equipment is fitted to passenger trains to manage the behaviour of wheel sets in low adhesion conditions. When the train is braking, it behaves like the
617:. To prevent wheel lock, on some routes trains are required to brake earlier and accelerate more slowly. Furthermore, some (passenger) trains are fitted with equipment to apply
562:
The cryptic nature of rail company explanations for slippery rail and related phenomena made the phrase "leaves on the line" a standing joke, and, along with variants such as "
486:
347:
system in cars by releasing the brake on any axle if it detects that it is locking up. WSP can also control the traction system to prevent wheel spin when applying power.
92:
leaves are deposited on the railhead. The build-up of this material is incremental, and it is hard enough not to be quickly worn away by the ordinary passage of trains.
793:
141:
of May 1851 noted that an accident was caused when a small locomotive hauling a heavy train was unable to find purchase on the rail because by the dirty state of the
519:
Metro-North has designed a system dubbed "Waterworld", which is a large flat rail car that blasts the rails with high-pressure water jets as the car moves over it.
290:
to volatilize the deposited material, but this method has only been used experimentally, as it is hindered by high power consumption, noise and rail degradation.
87:, many parts of Europe including the UK, and Southern Ontario, Canada, the problem can arise. Where the leaves fall onto a railway route, some collect on the
386:
Any information about the location and severity of low adhesion conditions will give train drivers warning of problems. In the UK there are several sources;
422:
Removal of deciduous trees at the lineside is a management method to control the problem; however, there is political resistance to this in populous areas.
302:
has used laser technology provided by Laser
Precision Solutions, to tackle the autumn slip slide issue, using two 25 mph (40 km/h) LaserTrains.
64:
between train wheels and rails, and in extreme cases can render the track temporarily unusable. In
Britain, the situation is colloquially referred to as "
478:
246:
In extreme cases, the build-up of leaf material can electrically insulate the wheels from the rails, resulting in a failure of signalling equipment to
367:. On the second run, the driver will experience the sound and sensation of the train sliding, and the stopping distance will be considerably greater.
1249:
1170:
921:
White, Ben; Kempka, Reuben; Laity, Peter; Holland, Chris; Six, Klaus; Trummer, Gerald; Buckley-Johnstone, Luke; Lewis, Roger (December 20, 2021).
1593:
1561:
1022:
2042:
1101:
748:
138:
1086:
253:
In the United
Kingdom, it was estimated that the poor adhesion problems cost the rail industry GBP 355 million (USD 449 million) a year.
1645:
1413:
Krier, Peter; White, Ben T; Ferriday, Paul; Watson, Mike; Buckley-Johnstone, Luke; Lewis, Roger; Lanigan, Joseph L (November 1, 2021).
129:
have increasingly been used, which means that cleaning the compressed leaf material from the wheel tread by abrasion no longer occurs.
2037:
1619:
314:
are fitted with sanders which apply a fine layer of dry sand on the railhead. This assists adhesion during braking and acceleration.
1864:
1754:
1318:
832:
198:
1675:
173:
to be penalised more than $ 700,000 for cancellations and poor punctuality in one quarter of 2001. In 2009, railway tracks at
1060:
622:
29:
Railhead
Treatment Train uses a high-pressure water jet to remove compressed leaf mulch from the rails in the United Kingdom.
1952:
1501:
79:
The leaf fall season causes the most disruption to rail operations. In heavily deciduous forested areas like the
American
1969:
516:, high-pressure water blasting and, most expensively, the use of high-powered laser blasts to clear the rails of leaves.
1701:
872:
971:
White, BT; Nilsson, R; Olofsson, U; Arnall, AD; Evans, MD; Armitage, T; Fisk, J; Fletcher, DI; Lewis, R (May 2, 2017).
972:
179:
378:
publish a special 'leaf fall' timetable to allow for the additional time that lighter braking and acceleration take.
322:
There are a range of novel methods being trialed for cleaning contamination from the railhead. One method uses solid
2012:
21:
1023:"The low adhesion problem due to leaf contamination in the wheel/rail contact: Bonding and low adhesion mechanisms"
601:
A term current in 2003 for cutting down or cutting back trees near the lines was "lineside vegetation management".
555:
In the United Kingdom, a number of rail companies change their timings and publish special "leaf fall timetables".
447:
430:
1201:
459:
1387:
1115:
446:
Slippery rail has created severe disruptions of rail service, particularly in major metropolitan areas such as
344:
405:
Lineside signs showing the start and end of known regular low adhesion areas are provided at some locations.
375:
364:
356:
1728:
1870:
610:
563:
513:
399:
338:
235:
97:
44:
where contamination of the railhead reduces the traction between the wheel and the rail. This can lead to
566:", is seen by members of the public who are not familiar with the problem as an excuse for poor service.
536:
467:
413:
normal conditions for the weather and conditions at that time of year, and report back to the signaller.
299:
271:
250:. Where the problem is severe, Track Circuit Actuators fitted to trains can help alleviate the problem.
1090:
283:
trains" after the original proprietary mixture applied) and in some cases locally by hand applicators.
455:
166:
45:
1340:
1653:
532:
161:
There are many substances which can cause low adhesion when they are deposited on the railhead. In
80:
1833:
1142:
1965:
1442:
1271:
1003:
980:
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
953:
903:
639:
522:
395:
126:
1502:"The Adhesion Rail Riddle - Ensuring Trains Can Brake | Engineering | University of Southampton"
923:"Iron Oxide and Water Paste Rheology and Its Effect on Low Adhesion in the Wheel/Rail Interface"
1414:
973:"Effect of the presence of moisture at the wheel–rail interface during dew and damp conditions"
1483:
1434:
1041:
995:
945:
895:
744:
738:
719:
435:
355:
Where trains have difficulty stopping during low adhesion conditions, the greatest risk is of
202:
187:
1994:
1935:
1890:
1224:
1473:
1426:
1033:
987:
937:
887:
711:
649:
634:
162:
149:
1296:
673:
363:
normal adhesion conditions. The railhead is then treated with a contaminant that has a low
2047:
2017:
1838:
1875:
1808:"What do you use to rescue a SEPTA gel train? Another SEPTA gel train! October 16, 2008"
1415:"Vehicle-based cryogenic rail cleaning: an alternative solution to 'leaves on the line'"
539:), and controlled at the other end by a former LIRR "Power Pack" cab unit (one a former
266:
582:
578:
451:
439:
323:
311:
231:
57:
41:
1807:
1780:
2031:
1679:
1446:
957:
907:
547:). However, as of 2015; The FA and F7 were retired and replaced by Comet 1 cab cars.
247:
142:
1007:
508:
Methods for dealing with slippery rail have included trimming trees, the release of
438:
is the silver/grey modified M3 car, with a red tank car to supply it) passes on the
1895:
891:
482:
76:
Railhead contamination caused by weather conditions can occur at any time of year.
26:
1911:
1529:
466:
lines' passenger cars being taken out of service. During the same period on the
1478:
1461:
463:
122:
84:
1037:
941:
715:
1974:
1587:"Online Rulebook – Module TW1 – Section 28.2 Arranging a controlled test stop"
873:"Simulation and understanding the wet-rail phenomenon using twin disc testing"
586:
498:
227:
194:
118:
88:
49:
1487:
1438:
1196:
1045:
999:
991:
949:
899:
723:
654:
502:
239:
174:
1430:
1250:"Improving track circuit actuation performance at the wheel/rail interface"
625:, to use lasers to remove contaminations was announced by NS and ProRail.
1916:
570:
61:
217:
1998:
1979:
644:
618:
614:
594:
590:
540:
490:
280:
206:
52:
when the train is braking. One common cause of contamination is fallen
1814:. The Philadelphia Chapter of the National Railway Historical Society
1787:. The Philadelphia Chapter of the National Railway Historical Society
1530:"National Rail Enquiries - Leaf Fall Timetable Changes - Autumn 2021"
1419:
Proceedings of the Institution of Civil Engineers - Civil Engineering
544:
505:
and Washington, D.C., have all reported delays due to slippery rail.
474:
170:
1119:
1462:"Microwave Plasma System for Continuous Treatment of Railway Track"
274:
work train pressure-washes the rail before applying a traction gel.
238:
to counter slippery rail conditions. Locked wheels can self-grind
574:
529:
494:
429:
265:
216:
183:
105:
20:
609:
Slippery rail is also a problem in the Netherlands, addressed by
1555:"Online Rulebook – Module TW1 – Section 28.1 Rail-head adhesion"
509:
53:
1781:"SEPTA Gel Train with F7 622 Philadelphia PA November 12, 2006"
1021:
Ishizaka, Kei; Lewis, Stephen R.; Lewis, Roger (May 15, 2017).
794:"Why your train is late when autumn leaves fall (free preview)"
470:, nearly 25% of cars were out of service due to slippery rail.
454:. In November 2006, it was blamed for roughly one-third of all
169:
which were crossing the tracks, caused passenger rail operator
226:
wheels may even lock up, causing the train to slide. Modern
197:
in 1938. Crushed locusts affected train operations on the
165:, Australia, train wheels crushing plagues of introduced
526:
delays due to wheelslip have been reduced by over 60%.
243:
wheels to be re-profiled or re-tyred at great expense.
193:
Slippery rails caused by caterpillars were reported in
776:. London, UK: First Capital Connect. September 2012.
60:. The condition results in significant reduction in
1460:Swan, Julian; Radoiu, Marilena (October 14, 2020).
774:
2012 Autumn & Winter Season (Drivers' Briefing)
569:Particularly problematic local trees include the
696:
694:
1388:"Track cleaning tech could prevent rail delays"
674:"Low Adhesion Mockery Sticks Despite the Facts"
1975:"Sandite: slim recept tegen blad op het spoor"
1061:"Disc brakes linked to rise in train "slides""
860:. London, UK: First Capital Connect. May 2012.
121:to stop the train by applying pressure on the
117:Before about 1960, most railway vehicles used
1955:, International Railway Journal, October 2003
1652:. New York. November 22, 2006. Archived from
1225:"Railway Group Standards - Railway Wheelsets"
56:that adhere to the railhead (top surface) of
8:
1116:"Royal Forestry Society: Leaves on the Line"
852:
850:
818:
816:
814:
768:
766:
764:
762:
760:
1729:"Commuters Warned Of "Slippery Rail" Delay"
1171:"Millipedes suspected in Perth train crash"
871:White, Ben; Lewis, Roger (August 1, 2019).
1091:"The fatal collision on the Sutton Tunnel"
479:Massachusetts Bay Transportation Authority
1891:"Wrong type of pressure halts new trains"
1477:
831:. White Plains, New York. Archived from
1912:"Going Loco – your bizarre train tales"
1859:
1857:
1727:Silberstein, Judy (November 15, 2006).
1197:"Caterpillars: Damage on Darling Downs"
1059:Wolmar, Christian (February 20, 1995).
825:"'Flat wheels' deflate train commuters"
823:Halbfinger, Caren (November 21, 2006).
792:Holmes, Elizabeth (November 21, 2006).
665:
1929:
1927:
1618:Aitchison, Gavin (November 21, 2006).
1319:"Permaquip Sand & Gel Applicators"
157:Low adhesion caused by crushed insects
1524:
1522:
1165:
1163:
787:
785:
783:
737:Desmond F. Moore (October 22, 2013).
7:
1889:Martin Wainwrightc (20 April 2004).
48:when the train is taking power, and
442:in autumn to deal with leaf issues.
1620:"Leaves on line cause rail delays"
1205:. Qld. October 24, 1938. p. 6
1143:"The millipedes which stop trains"
858:Summer Weather (Drivers' Briefing)
14:
1702:"Lasers clear leaves on the line"
743:. Elsevier Science. p. 311.
1646:"Commuters, expect train delays"
248:detect the presence of the train
199:Otavi Mining and Railway Company
16:Loss of traction in locomotives
1995:"Weg met die smurrie op spoor"
1141:Butler, Pip (April 29, 2002).
892:10.1016/j.triboint.2019.03.067
798:The Wall Street Journal online
623:Delft University of Technology
398:and form part of the drivers'
113:Disc brakes add to the problem
72:Low adhesion caused by weather
1:
2043:Transport and the environment
390:Regular blackspots, known as
1934:John May (22 October 2003).
133:Lack of lineside maintenance
1834:"Railhead Treatment Trains"
1812:Railfan Pictures of the Day
1785:Railfan Pictures of the Day
1479:10.3390/technologies8040054
402:which they are examined on.
392:Areas of known low adhesion
2064:
1910:Jon Yuill (25 July 2003).
1341:"Traction Gel Applicators"
1038:10.1016/j.wear.2017.02.044
942:10.1007/s11249-021-01549-0
716:10.1016/j.wear.2013.11.024
374:In the UK, some passenger
357:passing a signal at danger
336:
153:exacerbating the problem.
2038:Rail transport operations
1202:Townsville Daily Bulletin
493:'s commuter rail service
376:train operating companies
139:Commissioners of Railways
992:10.1177/0954409717706251
512:on the train wheels for
880:Tribology International
365:coefficient of friction
1871:Royal Forestry Society
1592:. RSSB. Archived from
1560:. RSSB. Archived from
1534:www.nationalrail.co.uk
1431:10.1680/jcien.21.00105
1367:www.masstransitmag.com
611:Nederlandse Spoorwegen
564:the wrong type of snow
443:
339:Wheel slide protection
333:Wheel slide protection
275:
236:Wheel slide protection
222:
137:A report by England's
30:
2001:. September 29, 2017.
1599:on September 29, 2011
1567:on September 29, 2011
1506:www.southampton.ac.uk
1230:. RSSB. February 2010
835:on September 30, 2007
543:, the other a former
537:West Chester Railroad
468:Long Island Rail Road
434:LIRR adhesion train (
433:
418:Vegetation management
394:are published in the
272:Long Island Rail Road
269:
220:
190:, in September 2013.
167:Portuguese millipedes
38:low railhead adhesion
24:
1865:"Leaves on the Line"
1755:"New Jersey Transit"
1297:"Leaves on the line"
1032:. 378–379: 183–197.
456:Metro-North Railroad
42:railways (railroads)
40:, is a condition of
1878:on 17 January 2008.
1682:on November 9, 2006
1656:on January 24, 2013
1177:. September 3, 2013
257:Mitigation measures
2021:. August 14, 2014.
640:Sandbox (railways)
593:, which regrow or
523:New Jersey Transit
444:
396:Sectional Appendix
276:
262:Railhead treatment
234:are equipped with
223:
66:leaves on the line
31:
2013:"NS zet laser in"
1806:Almeida, John P.
1779:Almeida, John P.
1759:www.njtransit.com
1733:Larchmont Gazette
1394:. October 5, 2021
930:Tribology Letters
750:978-1-4831-5728-3
351:Driving technique
203:South-West Africa
188:Western Australia
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1735:. New York State
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1129:
1127:
1122:on July 13, 2013
1118:. Archived from
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1106:
1105:
1104:. pp. 7, 9.
1102:House of Commons
1098:Railways Archive
1095:
1089:(May 22, 1851).
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829:The Journal News
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710:(1–2): 213–219.
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635:Adhesion railway
310:Locomotives and
150:steam locomotive
100:during braking.
2063:
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1970:Wayback Machine
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1964:Archived at
1960:
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1939:
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1868:
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1837:
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1816:. Retrieved
1811:
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1680:the original
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1654:the original
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1640:
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1628:. Retrieved
1623:
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1466:Technologies
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1392:The Engineer
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1366:
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1291:
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1252:. RSSB. 2011
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1120:the original
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1712:January 22,
1372:November 3,
1363:"StackPath"
1325:December 8,
1321:. Permaquip
1303:December 8,
1256:December 6,
1234:December 8,
886:: 475–486.
605:Netherlands
473:In the US,
228:locomotives
127:disc brakes
119:brake shoes
98:wheel slide
85:New England
2032:Categories
1706:Physicsweb
1343:. JSD Rail
1272:"Adhesion"
1209:October 8,
678:Rail.co.uk
661:References
559:build up.
240:flat spots
195:Queensland
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1624:The Press
1539:April 26,
1511:March 25,
1488:2227-7080
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655:Tribology
613:(NS) and
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409:Appendix.
221:Flat spot
175:Tallarook
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1968:and the
1917:BBC News
1126:July 21,
1071:July 21,
1067:. London
1008:55583850
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629:See also
571:sycamore
514:traction
448:New York
205:(modern
180:Clarkson
163:Victoria
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62:friction
1999:ProRail
1980:YouTube
1953:Article
1846:1 April
1676:"SEPTA"
1650:WABC-TV
1181:May 26,
1152:May 26,
1147:The Age
645:Sandite
619:Sandite
615:ProRail
595:coppice
541:ALCO FA
491:Chicago
306:Sanders
281:Sandite
213:Effects
207:Namibia
148:In the
2048:Leaves
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464:Harlem
460:Hudson
452:Boston
294:Lasers
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1597:(PDF)
1590:(PDF)
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1839:Rail
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