more about rail fastening system

Jan 13, 2017

Function of rail fastening system

A rail fastening system is the whole set fasteners that are used to join the rails and railroad ties (or other type of rail foundation). Normally, rail fastening system is consist of rail spike, rail bolt, rail clip, tie plate, rail pad and plastic dowel, etc. Rail fastening system is also known as an intermediate coupling part. On the whole, railway fastening system plays a role in fixing rails to the sleepers, maintaining the gauge and preventing longitudinal and lateral movement of the rail relative to the sleeper.

History of rail fastening system

In the earliest day, rail fastener means peg or nail that is used to fix wooden rail to wooden railway sleeper.
By the 18^th century, cast iron railways had put into application, which is easy to be fixed by the railway fasteners. At the same time, the first rail chair was applied in the railway in 1797.
In the 1830s, the flanged’ tee’ rail was invented by Robert L. Stevens. This kind of rail is actually a distorted I beam, and it needn’t a chair.
Finally, flanged T railway become popular in the world, which require the rail fastening system to support.

Features of rail fastening system

According to the requirement of railway track transportation, rail fastening system should have the following characteristics:

With sufficient strength and durability
With adjustability of gauge and horizontal
With good insulation properties
With good damping elasticity
With compatibility and interchangeability

Types of rail fastening system

For different applications, railway fastening system can be divided into various types. Each type of rail fastening system has its components, which is different with other types. Rail fastening system is typically named after the types of rail clip, such as skl rail fastening system, e-clip rail fastening system, kpo rail fastening system, nabla rail fastening system, etc.

SKL clip rail fastening system

Generally, the components of SKL rail fastening system include SKL tension clip, screw spike, flat washer, plastic dowel, guide plate and rail pad. Skl rail fastening system is used with concrete sleepers.

Part Name	Type	Material	Surface	Remark
SKL tension clip	Dia. 13mm	60Si2CrA, 38Si7	Plain oiled, color painting, or the other required ones.	Hardness: 42-47HRC Fatigue test: When the clip spring deflection reaches 9.1mm and the swing deflection is 1.42mm, the fatigue life will be 5 millions cycles without breaking. Standard: DIN17221, GB/T1222
screw spike	M24150MM M24160MM M24*180MM	Grade 4.6: Q235 Grade 5.6: 35# Grade 8.8: 45#	Plain oiled, black oxide, galvanized, hot dip galvanized, Dacromet and sherardized	Standard: ISO898-1, UIC864-1 and NF F500-50
plain washer	UIs7	Q235	Plain oiled, black oxide, galvanized, hot dip galvanized, Dacromet and sherardized	Standard: EN10025, EN10139
plastic dowel	For different size of screw spike	HDPE, Reinforced Nylon 66 (PA66)	Black, blue, yellow, green or other color	For insert into concrete sleeper
guide plate	UIC54, UIC60, 50kg rail, 6kg rail, and other sizes as ordered	Reinforced Nylon 66 (PA66)	Black, blue, yellow, green or other color	Different designs are available.
rail pad	UIC54, UIC60 and sizes as ordered	EVA, or rubber	Black, blue, yellow, green or other color	Different designs are available.

E-clip rail fastening

For E-clip fastening system, E-clip, shoulder, rail pad, insulator are necessary parts.

Part Name	Type	Material	Surface	Remark
E clip	Dia. 16mm Dia. 18mm Dia. 20mm	60Si2MnA, 60Si2CrA,55SiMn	Plain oiled, color painting, or the other custom finish.	Hardness: 44-48HRC Toe Load: 500-700kgf for Dia.16mm 750-900kgf for Dia.18mm 1100-1400kgf for Dia.20mm Fatigue life:3 millions cycles without breaking for Dia.18mm, 5 millions cycles without breaking for Dia.20mm Standard: DIN17221, BS970, GB/T1222
Shoulder	UIC54,UIC60, 115RE,50kg rail, 60kg rail,BS80lbs, BS100lbs	QT500-7 QT450-10	Plain oiled, color painting	Different designs are available.
Rail pad	UIC54,UIC60, BS80lbs,BS100lbs, in ordered size	HDPE, EVA, or rubber	Black or other colors	Different designs are available.
Insulator	UIC54,UIC60, 50kg rail, 60kg rail, BS80lbs,BS100lbs, and size as ordered	Reinforced Nylon 66 (PA66)	Black, blue, yellow, green or other color	Different designs are available.

KPO clip rail fastening system

KPO rail fastening system is usually consist of KPO clips, screw spikes, HS bolts, Hex nuts and double coil spring washer.

Part name	Type	Material	Surface	Remark
KPO clip	KPO3, KPO6, KPO9	Q235	Plain oiled	Standard: DIN5906
HS bolt	HS26, HS32	Grade4.6: Q235 Grade5.6: 35# Grade8.8: 45#	Plain oiled, black oxide, galvanized, hot dip galvanized	Diameter: 22mm or 24mm. Length: 55mm, 65mm, 75mm, 90mm Standard: UIC864-2
Hex nut	As ordered	Grade 5: 35# Grade 8: 45#	Plain oiled, black oxide, galvanized, hot dip galvanized	Standard: DIN985
Double coil spring washer	As ordered	65Mn	Plain oiled, black oxide, galvanized, hot dip galvanized	Standard: UIC864-3
screw spike	M24×150mm M24 ×160mm M24 ×180mm other length	Grade 4.6: Q235 Grade 5.6: 35# Grade 8.8: 45#	Plain oiled, black oxide, galvanized, hot dip galvanized, Dacromet and sherardized.	Standard: ISO898-1, UIC864-1 NF F500-50
Base plate	UIC54,UIC60, 50kg rail, 60kg rail,S49 in ordered size	Casting iron QT500-7, QT450-10, or forging low carbon steel or high carbon steel	Plain oiled	Standard: UIC864-6

Nabla clip rail fastening system

Structurally, a Nabla clip rail fastening system contains these parts like nabla clips, insulator, double end screw spike, special spring washer, hex nut and plain washer.

Part name	Type	Material	Surface	Remark
Nabla clip	Thickness 4mm or 4.5mm	60Si2MnA, 60Si2CrA	Plain oiled, red color painting, or the other required by customers	Hardness: 42-47HRCFatigue life: 3 millions cycles without breaking Standard: DIN17221, GB/T1222
Insulator	UIC54, UIC60, S49 rails	Reinforced Nylon 66 (PA66)	Black, blue, yellow, green or other colors	Different designs are available.
Double end screw spike	UIC54, UIC60, 50kg rail, 60kg rail	Grade 5.6: 35#	Plain oiled, black oxide, galvanized, hot dip galvanized	Bending at 30 degree without crack.
Special spring washer	18.25×34×78mm	ML08Al	Plain oiled, black oxide, galvanized, hot dip galvanized	For protecting the thread of the double end screw spike
Hex nut	As ordered	Grade 5: 35#	Plain oiled, black oxide, galvanized, hot dip galvanized	Standard: DIN985
Plain washer	As ordered	Q235	Plain oiled, black oxide, galvanized, hot dip galvanized	Standard: DIN125

In conclusion, rail fastening system should be able to maintain the reliable connection between rail and railway sleeper effectively over a long period of time. Under the dynamic action, railway fastening system must give full play to its damping and the buffer performance. Besides typical types of railway fastening system mentioned above, there are many other kind of rail fastening system on the market, including high speed WJ series rail fastening system, type IV rail fastening system, fast clip rail fastening system and SFC fastening system etc.