E-Type and Tension Rail Clips for Elastic Railway Fastening Systems

Elastic rail clips are core components of railway fastening systems. They press the rail against the sleeper or baseplate through controlled elastic deformation and hold it firmly in place over the service life of the track. By maintaining continuous clamping force, elastic clips prevent the rail from moving vertically or horizontally relative to the sleeper, keep the track gauge stable, and absorb part of the impact energy generated by passing trains.

What Are E-Type and Tension Rail Clips

E-type rail clips take their name from the letter E shape of the formed spring steel bar. They are among the most widely used elastic fasteners in ballasted track systems. Tension clamps are closed-loop clips that are driven over an embedded shoulder cast into the sleeper. Both designs rely on the elasticity of spring steel rather than bolts to generate the clamping force that holds the rail down.

Spring Steel Grades and Standards

High quality elastic clips are made from spring steel bars with high yield strength and good fatigue resistance. Common grades include 60Si2MnA, 60Si2CrA, 55Si2Mn, and 38Si7. The chemical composition of 60Si2MnA is carbon 0.56 to 0.64 percent, manganese 0.60 to 0.90 percent, silicon 1.60 to 2.00 percent, chromium up to 0.35 percent, with phosphorus and sulfur each limited to 0.03 percent. Controlled compositions are applied to the other grades so that heat treatment produces a consistent hardness of 44 to 48 HRC for E-type clips and 42 to 47 HRC for tension clamps.

Production follows established material and fastening standards including DIN 17221 for spring steel, BS 970 for wrought steels, and GB/T 1222 for spring steel products. Finished clips are supplied with plain oiled, oxide black, or painted surfaces, or with customer specified finishes.

Typical Specifications

Tension clamps are produced in 13 mm and 14 mm bar diameters with a hardness of 42 to 47 HRC. Fatigue testing shows that 18 mm clips withstand at least 3 million load cycles without breaking, while 20 mm clips withstand at least 5 million cycles.

How Elastic Rail Clips Perform in Service

Rail clips work under repeated alternating stress. Each passing wheel applies bending, torsion, and impact loads, so the clip must combine high strength with enough elasticity to recover its original shape. The elastic structure converts part of the impact energy into spring deformation, which reduces vibration transmitted to the sleeper and lowers the fatigue load on the entire track structure.

Selection and Installation Points

Select the clip diameter and model according to the rail section, sleeper type, and required clamping load. Clips with larger bar diameters and higher toe loads suit heavy haul and high speed lines, while lighter clips suit branch lines and secondary tracks. During installation the clip must be fully seated in its shoulder so that the front claw contacts the rail insulator correctly. After installation, check the toe clearance and confirm that the clip cannot lift off under load.

Frequently Asked Questions

What is the difference between an E-type clip and a tension clamp? n E-type clip is an open clip that is driven over the rail base, while a tension clamp is a closed loop that engages an embedded shoulder. Both generate clamping force through spring steel elasticity.

Which material is used for elastic rail clips? Spring steel grades such as 60Si2MnA, 60Si2CrA, 55Si2Mn and 38Si7 are commonly used because they combine high yield strength with excellent fatigue life.

What hardness should an E-type rail clip have? E-type clips are typically hardened to 44 to 48 HRC, while tension clamps are usually 42 to 47 HRC.

How many load cycles can a rail clip survive? In fatigue testing, 18 mm clips survive at least 3 million cycles and 20 mm clips at least 5 million cycles without breaking.

What surface finishes are available? Plain oiled, oxide black and color painted finishes are standard, and customer specified finishes can be arranged.