Rail Fastening System

 

Rail fastening systems secure steel rails to railway sleepers. They maintain track gauge, absorb vibration, and resist vertical and lateral forces. The primary systems—often distinguished by their rail clips—include the E-clip, Pandrol Fast Clip, SKL, KPO systems,etc.

 

 

The SKL Fastener System is a globally utilized railway track fastening system designed to securely anchor steel rails to concrete sleepers (ties) on ballasted tracks. Its highly elastic design absorbs vibrations, prevents rail shifting, and ensures long-term structural stability for both high-speed and heavy-load railways.

 

• W12 Fasteners System

 

 

Main Components	Quantity
Tension clamp W12	2pcs
Base Plate	1pc
Clip Bolt HS32 with Hex Nut and Washer	2pcs
Rail Pad	1pc
Under Base Plate Sole Pad	1pc
Double Spring Washer	4pcs
Sleeper Screw Ss8	4pcs

 

• W14 Fasteners System

 

 

No.	Item	Spec.	Material	Coating	Quantity	Unit
1	W14 Rail Fastening System				1	Sleeper Sets
1.1	Plastic Nylon Screw Dowel	31*165mm	PA6		4	Pcs
1.2	Rail Pad	199*158*6mm	EVA		2	Pcs
1.3	Angled Guide Plate	Wfp-14k	Reinforced PA66		4	Pcs
1.4	Tension Clamp	SKL-14	60Si2Mn, 60Si2Cr, 38Si7	Electrostatic painting, Darcoet, Hot-dip galvanizing, Sherardizing	4	Pcs
1.5	Sleeper Screw with Plate Washer	Screw: 24*161, Washer:25*25*3.5	Screw: 35# Plate: Washer: Q235, Screw: Class 5.6	Darcoet, Hot-dip galvanizing, Sherardizing	4	Pcs

 

• W21 Fasteners System

 

 

Part name	Type	Material	Finish	Remark
SKL21 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
Ss35 screw spike	M24×150mm M24 ×160mm 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	Uls7	Q235	Plain oiled, black oxide, galvanized, hot dip galvanized, Dacromet and sherardized	Standard: EN10025, EN10139
Plastic dowel	For different sizes 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, 60kg 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 size as ordered	EVA, or rubber	Black, blue, yellow, green or other color	Different designs are available

 

• W30 Fasteners System

 

Name	Weight/unit	Quantity pcs.	Total weight (kg).
Tension clamp：Skl-30	0.7	4	0.28
Sleeper Screw：Ss 25, Ss 35 with washer Uls	0.68	4	2.72
Angle guide plate：Wfp14/ 30 KNT	0.17	4	0.68
Plastic Dowel：Sdu 9, Sdu 25	0.033	4	0.132
Gasket：Zw 700/1000d NT	0.16	2	0.32

 

 

The E-clip fastening system (originally pioneered by Pandrol) is a widely used, threadless rail securing assembly. Made of high-strength spring steel, it provides permanent elastic clamping to hold steel rails to sleepers. It absorbs heavy vibrations while preventing track shifting and accommodating thermal expansion.
 

 

Item included	Quantity	Material	Size	Remark
E clip	4	60Si2MnA, 60Si2CrA	Dia. 16mm,18mm or 20mm (E1809, E2006,E2007,E2009,etc	Hardness: 44-48HRC
				Toe Load: Dia.16mm: 500-700kgf; Dia.18mm:750-900kgf; Dia.20mm:1100-1400kgf
				Fatigue life: 5 millions cycles without breaking
				Standard: DIN17221, BS970, GB/T1222
Shoulder	4	QT500-7, QT450-10	For UIC54, UIC60, 115RE, BS80lbs, BS100lbs, 50kg rail, 60kg rail, etc.	Note: Hardness of E-clip is 44-48HRC; Toe Load for E-clip is 500-700kgf (Dia.16mm); 750-900kgf(Dia.18mm); 1100-1400kgf(Dia.20mm); Fatigue life of E-clip is 5 millions cycles without breaking DIN17221, BS970, GB/T1222 qualified E-clip
Rail pad	2	HDPE, rubber or EVA
Insulator	4	Reinforced Nylon 66 (PA66)

 

 

The Fastclip rail fastening system is a resilient, threadless clip system designed to secure rails to sleepers or slab tracks. Its unique "switch-on, switch-off" bolt-free design allows for rapid installation, reduced maintenance costs, and automatic clamping force.

 

 

Component (per railseat)	Remarks	Part No.
FASTCLIP FC rail clip (2)	Spring steel	Refer to assembly drawing
Toe insulator (2)	HVN
Pad - rail (1)	Rubber, EVA, Polyurethane options as required
Sidepost (2)	HVN
Shoulder (2)	SG Iron – Cast in Sleeper

 

 

The Nabla Fastening System is a widely used, dynamically stable track fastener renowned for its use in tramways, metros, and high-speed rail. It is prized for its high clamping force, excellent electrical insulation, and exceptional ability to maintain track gauge on tight radius curves.

 

 

Item	Part Name	Pcs / Set	Types	Material
1	Nabla Clip	2	Thickness: 4mm or 4.5mm	60Si2MnA 60Si2CrA
2	Rail Insulator	2	For Rail of UIC54,UIC60, 50kg rail,60kg.	Reinforced Nylon 66 or PA66
3	Screw Spike	2	For Rail of UIC54,UIC60, 50kg rail,60kg.	Grade 4.6: Q235; Grade 5.6: 35# Grade 8.8: 45#
4	Nut	2	Can be customized	Grade 5: 35# Grade 8: 45#
5	Spring Washer	2	18.25x34x78mm	65Mn

 

 

The FIST rail fastening system is a boltless, elastic assembly developed in Sweden, designed to secure steel rails to railway sleepers. Known for rapid installation and durability, it is heavily used in heavy-load, high-speed, and mining railways across Australia, South America, and Southern Africa.

 

 

Item Name	Railway Fist clip Fastening System
Usage	Rail Fastening
Material	38Si7, 60Si2MnA, 60Si2CrA, 55Si2Mn
Surface Treatment	Bluing, Plain Oiling, Color Painting, etc
Documents with Delivery	Mechanical Properties, Chemical Composition, All Sizes Reports
Standard	DIN17221, BS970, GB/T1222

 

 

The KPO Clamp Fastening System is a heavy-duty, adjustable track fastener widely used across the globe for railway, heavy-haul, crane, and mining tracks. It provides high clamping force and secure lateral adjustment, ensuring rails remain firmly locked under extreme stress and harsh environmental conditions.

 

 

Part name	Pieces required	Material	Type	Note
KPO clamp	4	Q235	KPO3, KPO6, KPO9	Standard: DIN5906
Screw spike	8	Grade 4.6: Q235 Grade 5.6: 35# Grade 8.8: 45#	M24×150mm M24 ×160mm M24 ×180mm	Standard: ISO898-1, UIC864-1 and NF F500-50
HS bolt	4	Grade4.6: Q235 Grade5.6: 35# Grade8.8: 45#	HS26, HS32	Diameter: 22mm or 24mm. Length: 55mm, 65mm, 75mm, 90mm
Hex nut	4	Grade 5: 35# Grade 8: 45#	As ordered	Standard: DIN985
spring washer	8	65Mn	As ordered	Standard: UIC864-3
Base plate	2	Casting iron QT500-7, QT450-10, or forging low carbon steel or high carbon steel;	UIC54,UIC60, 50kg rail, 60kg rail,S49 in ordered size	Standard: UIC864-6

 

 

A rail spike fastening system secures steel rails to railroad ties (sleepers), preventing lateral and longitudinal movement while maintaining track gauge. It primarily consists of metal spikes (like cut, screw, or elastic spikes), tie plates, clips, and rail pads.

 

 

Item	Track/Cut spike	Tie plate
Quantity	5	1
Material	Q235A	QT450-10 for casting Q235 for rolling

 

 

The WJ-7 Rail Fastening System is a specialized ballastless track fastener used primarily in high-speed railways, subways, and passenger-dedicated lines. Optimized for tracks without shoulders, it provides superior elasticity, vibration reduction, and structural versatility to ensure safe, high-speed train operations.

 

 

Serial number	Name	Quantity	Material	Mass or volume	Remarks
1	T-bolt T1	2	Q235-A	0.76 kg
2	Nut M24	2	Q235-A	0.224 kg
3	Flat Washers	2	Q235-A	0.138 kg
4	W1 type elastic bar	2	60Si2MnA	1.44 kg	Choose one according to the line resistance.
	X2 type elastic bar			1.22 kg
5	WJ7 insulation block	2	Glass fiber reinforced polyamide 66	72.6 cm3
6	WJ7 iron pad	1	QT450-10	10.2 kg
7	WJ7 insulation cushion board	1	Rubber	420 cm3
8	WJ7-A rubber pad	1	rubber	270 cm3	The speed is 250km/h for passenger dedicated lines, and one of them is selected according to the specific requirements of line resistance.
	WJ7-A composite pad		rubber	270 cm3
			stainless steel	0.24 kg
	WJ7-B rubber pad		rubber	325 cm3	The speed is 350km/h for passenger dedicated lines, and one of them is selected according to the specific requirements of line resistance.
	WJ7-B composite pad		rubber	325 cm3
			stainless steel	0.24 kg
9	Anchor bolt B1	2	Q235-A	2.20 kg
10	Heavy duty spring washer 30	2	65Mn, 60Si2Mn	0.09 kg
11	WJ-7 flat pad	2	QT450-10	0.50 kg
12	Pre-embedded casing D2	2	Glass fiber reinforced polyamide 66	200 cm3
13	WJ7 rail heightening pad		Polyethylene	27.7 cm3/mm	According to the specific situation
14	WJ7 iron pad down the high pad		Rubber	310 cm3/5mm	According to the specific situation

 

 

The WJ-8 Rail Clip Fastening System is an advanced, non-separated ballastless track fastener used primarily for high-speed railways, urban metros, bridges, and tunnels. Designed to handle speeds of up to 350 km/h, it ensures track stability, maintains precise rail gauge, and absorbs dynamic vibrations.

 

 

Serial number	Name	Quantity	Material	Mass or volume	Remarks
1	Spiral spike	2	High quality carbon steel or alloy steel	1.50kg	The S2 type is generally used, and the S3 type is used when the height is greater than 15 mm.
2	Flat Washers	2	Q235-A	0.138kg
3	W1 type elastic clip	2	60Si2MnA	1.44kg	The general section adopts the W1 type, the single elastic rail clip buckle pressure is greater than 9kN, and the elastic stroke is 14mm.
	X2 type elastic clip			1.28 kg	The X2 type is used for the small resistance area. The single spring buckle has a pressure of 6kN and a stroke of 12mm.
4	WJ8 insulation block	2	Glass fiber reinforced nylon PA66	79.0cm3	Type I, used in general locations.
				73.0cm3	Type II, used at rail joints.
5	WJ8 gauge baffle	2	Glass fiber reinforced nylon PA66	718cm3	Normal installation No. 7, select different numbers according to the gauge adjustment. Joint gauge baffle at rail joint
	WJ8 joint gauge baffle
6	WJ8 rubber pad	1	Natural rubber or synthetic rubber	140cm3	Select one of them according to the specific requirements of the line resistance. The composite backing plate is formed by vulcanizing a 1.2 mm thick 1Cr18Ni9Ti stainless steel plate and rubber. Do not use reclaimed rubber
	WJ8 composite pad		rubber	110cm3
			stainless steel	0.25kg
7	WJ8 iron rail pad	1	QT450-10	6.80kg
8	WJ8 iron rail pad under the rail pad	1	Thermoplastic elastomer (foaming pad)	540cm3	The static stiffness of the A-type pad is 30~40 kN/mm, which is suitable for the 250 km/h passenger dedicated line (considering freight transportation);
					The static stiffness of the B-type pad is 20~26 kN/mm, which is suitable for the 350 km/h passenger dedicated line; the dynamic and static stiffness ratio is not more than 2.0.
9	Pre-embedded casing D1	2	Glass fiber reinforced nylon PA66	115cm3	The pull-out resistance of the embedded bushing in the sleeper is not less than 60kN.
10	WJ8 under-rail fine-tuning pad	1	Polyethylene injection molding	25cm3/mm	According to the specific situation
11	WJ8 iron rail pad down the high pad	2	Polyethylene injection molding	720cm3/10mm	According to the specific situation

 

 

A rail fastening system is a critical engineering component used to fix steel rails to the underlying railroad ties (sleepers) or concrete base. Its primary purpose is to ensure the integrity, safety, and stability of the track structure under dynamic wheel loads.

 

1. Maintaining Track Gauge and Alignment

 

The most critical function of a fastening system is to maintain track gauge (the distance between the inner faces of the two rails) and prevent rail rollover. When a train passes, especially along curves, it exerts immense lateral forces. The fastening system locks the rail securely in place to resist these lateral and vertical movements, preventing derailments caused by gauge widening.

 

2. Longitudinal Creep Resistance

Trains generate significant longitudinal forces during acceleration and braking. Additionally, thermal expansion and contraction cause steel rails to move along their length. Fastening systems provide continuous longitudinal clamping force (toe load) to grip the rail foot tightly, preventing the rail from "creeping" or shifting longitudinally.

 

3. Load Distribution and Transfer

A rail fastening system acts as the primary medium to transfer heavy, dynamic wheel loads from the rail to the sleepers and down to the ballast or concrete foundation.

 

• Tie Plates / Base Plates: These expand the contact area under the rail foot, distributing the concentrated vertical load over a larger surface area on the sleeper to prevent the rail from cutting into the tie.

 

 

4. Vibration Damping and Shock Absorption

Modern rail fastening systems incorporate elastic components, such as rubber or polyurethane rail pads, positioned directly under the rail foot.

These pads absorb the high-frequency vibrations and shock impacts generated by the wheel-rail interface.

Reducing these vibrations protects the underlying sleepers and ballast from premature degradation, extending the lifespan of the entire track infrastructure.

 

5. Electrical Insulation

In modern railway networks, the rails are frequently utilized as conductors for track circuits (signal systems) or return currents for electric traction. Fastening systems utilize non-conductive components—such as plastic or nylon insulators and specialized dowels—to isolate the rail electrically from the sleepers and the ground. This prevents signal interference and controls stray current corrosion.

 

 

The inspection frequency for a rail fastening system is not uniform; it is determined by a combination of track class, traffic density (measured in Million Gross Tons, or MGT), operating speed, and environmental conditions. Railway authorities operate under strict regulatory frameworks to balance safety with maintenance costs.

 

 

Here is a breakdown of typical inspection intervals, methods, and key indicators of degradation.

 

1. Standard Inspection Frequencies

 

Track Type / Condition	Inspection Frequency	Primary Method
High-Speed Rail & Heavy Haul Lines	Daily to weekly	Automated Track Inspection Vehicles (ATGMS / Vision Systems)
Mainline Freight / Passenger Lines	Every 1 to 4 weeks	Visual walking/hi-rail inspection & automated geometry cars
Light Rail / Transit Systems	Monthly to quarterly	Visual walking inspection & manual spot-checks
Industrial Sidings & Yard Tracks	Bi-annually to annually	Manual walking inspection
Extreme Weather / Thermal Events	Immediate (Ad-hoc)	Targeted foot patrols

 

2. Critical Inspection Parameters & Deficiencies

 

During any inspection, personnel and automated vision systems look for specific signs of failure or wear that compromise the system's purpose:

 

 

• Missing or Broken Clips: Elastic clips (such as E-clips or SKL clips) can fracture due to fatigue, or back out of their shoulders from extreme vibration.

 

• Loose or Slipped Fasteners: Screw spikes or bolts backing out of concrete dowels or wooden sleepers, leading to a loss of toe load (clamping force).

 

• Insulator Degradation: Crushed, cracked, or missing nylon insulators, which leads to metal-on-metal contact and immediate electrical isolation failure.

 

• Rail Pad Crushing/Extrusion: Rubber or polyurethane pads wearing thin, cracking, or shifting out from under the rail foot, reducing vibration damping and causing rail seat abrasion.

 

• Component Corrosion: Severe rust on clips or base plates, particularly in coastal areas, tunnels, or wet environments, which accelerates mechanical failure.

 

3. Special Factors Requiring Increased Frequency

 

Standard schedules are frequently accelerated under the following conditions:

 

• Sharp Curves: Fasteners on tight curves experience significantly higher lateral forces and lateral wear, requiring more frequent checks for gauge widening and clip displacement.

 

• Turnouts and Crossovers: Switch areas handle complex dynamic forces and wheel impacts, making them high-priority inspection zones.

 

• Extreme Seasonal Changes: Rapid temperature swings cause severe longitudinal rail expansion and contraction, putting maximum stress on the creep resistance of the fasteners. Foot patrols are often deployed during peak summer heat to check for rail buckling risks.

 

 

 

 

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