Types Railroad tie

1 types

1.1 stone block
1.2 wooden
1.3 concrete
1.4 steel
1.5 plastics

types
stone block

stone block kilmarnock , troon railway.

the type of railroad tie used on predecessors of first true railway (liverpool , manchester railway) consisted of pair of stone blocks laid ground, chairs holding rails fixed blocks. 1 advantage of method of construction allowed horses tread middle path without risk of tripping. in railway use ever heavier locomotives, found hard maintain correct gauge. stone blocks in case unsuitable on soft ground, such @ chat moss, timber ties had used. bi-block ties tie rod similar.

wooden

a variant fastening of rails wooden ties

historically wooden rail ties made hewing axe, called axe ties or sawn achieve @ least 2 flat sides. variety of softwood , hardwoods timbers used ties, oak, jarrah , karri being popular hardwoods, although increasingly difficult obtain, sustainable sources. lines use softwoods, including douglas fir; while have advantage of accepting treatment more readily, more susceptible wear cheaper, lighter (and therefore easier handle) , more readily available. softwood treated, while creosote common preservative railway ties, preservatives used such pentachlorophenol, chromated copper arsenate , few other preservatives. non-toxic preservatives used, such copper azole or micronized copper. new boron-based wood preserving technology being employed major railroads in dual treatment process in order extend life of wood ties in wet areas. timbers (such sal, mora, jarrah or azobé) durable enough can used untreated.

problems wooden ties include rot, splitting, insect infestation, plate-cutting, known chair shuffle in uk (abrasive damage tie caused lateral motion of tie plate) , spike-pull (where spike gradually loosened tie). more information on wooden ties railway tie association maintains comprehensive website devoted wood tie research , statistics.

wooden ties can, of course, catch fire; age develop cracks allow sparks lodge catch fire more easily.

concrete


concrete ties on bnsf line north of yakima, washington

concrete ties cheaper , easier obtain timber , better able carry higher axle-weights , sustain higher speeds. greater weight ensures improved retention of track geometry, when installed continuous-welded rail. concrete ties have longer service life , require less maintenance timber due greater weight, helps them remain in correct position longer. concrete ties need installed on well-prepared subgrade adequate depth on free-draining ballast perform well. concrete ties amplify wheel noise, wooden ties used in densely populated areas.

on highest categories of line in uk (those highest speeds , tonnages), pre-stressed concrete ties ones permitted network rail standards.

most european railways use concrete bearers in switches , crossing layouts due longer life , lower cost of concrete bearers compared timber, increasingly difficult , expensive source in sufficient quantities , quality.

steel

steel ties

steel ties formed pressed steel , trough-shaped in section. ends of tie shaped form spade increases lateral resistance of tie. housings accommodate fastening system welded upper surface of tie. steel ties in widespread use on secondary or lower-speed lines in uk have been found economical install due ability installed on existing ballast bed. steel ties lighter in weight concrete , able stack in compact bundles unlike timber. steel ties can installed onto existing ballast, unlike concrete ties require full depth of new ballast. steel ties 100% recyclable , require 60% less ballast concrete ties , 45% less wood ties.

historically, steel ties have suffered poor design , increased traffic loads on long service life. these aged , obsolete designs limited load , speed capacity can still found in many locations globally , performing adequately despite decades of service. there great numbers of steel ties on 50 years of service , in cases can , have been rehabilitated , continue perform well. steel ties used in specialty situations, such hejaz railway in arabian peninsula, had ongoing problem bedouins steal wooden ties campfires.

modern steel ties handle heavy loads, have proven record of performance in signalized track, , handle adverse track conditions. of high importance railroad companies fact steel ties more economical install in new construction creosote-treated wood ties , concrete ties. steel ties utilized in sectors of worldwide railroad systems including heavy-haul, class 1s, regional, shortlines, mining, electrified passenger lines (ohle) , manner of industries. notably, steel ties (bearers) have proven on last few decades advantageous in turnouts (switches) , provide solution ever-growing problem of long timber ties such use.

when insulated prevent conduction through ties, steel ties may used track circuit based train detection , track integrity systems. without insulation, steel ties may used on lines without block signaling , level crossings or on lines use other forms of train detection such axle counters.

plastics

klp hybrid plastic railroad tie



tie placer in hyannis, massachusetts

in more recent times, number of companies selling composite railroad ties manufactured recycled plastic resins, , recycled rubber. manufacturers claim service life longer wooden ties expected lifetime in range of 30–80 years, ties impervious rot , insect attack, , can modified special relief on bottom provide additional lateral stability. in main track applications hybrid plastic tie has recessed design surrounded ballast.

aside environmental benefits of using recycled material, plastic ties replace timber ties soaked in creosote, latter being toxic chemical, , recyclable. hybrid plastic railroad ties , composite ties used in other rail applications such underground mining operations, industrial zones, humid environments , densely populated areas. hybrid railroad ties used partly exchanged rotten wooden ties, result in continuous track stiffness. hybrid plastic ties , composite ties offer benefits on bridges , viaducts, because lead better distribution of forces , reduction of vibrations respectively bridge girders or ballast. due better damping properties of hybrid plastic ties , composite ties, decrease intensity of vibrations sound production.

in 2009, network rail announced begin replacing wooden ties recycled plastic ones made i-plas ltd of halifax, west yorkshire; i-plas became insolvent in october 2012.

the cable tv series factory made has segment on manufacture of plastic ties.

in 2012, new zealand ordered trial batch of ecotrax brand recycled composite ties axion use on turnouts , bridges, axion filed bankruptcy in december 2015. these ties developed dr. nosker @ rutgers university.

in 2014 klp hybrid plastic tie, lankhorst engineered products of sneek, netherlands, won privatbahn magazin innovation award in category track , infrastructure.

ties may made fiberglass.