What Types of Rail Clamps Are There? A Practical Classification

How Are Rail Clamps Classified?

Rail clamps, also called rail clips, are categorised by design, application and installation method. By design they range from E-type elastic clips and tension clips to heavy-section clamps for crane rails. By installation they are bolted, welded or driven/pressed into place. By application they cover general railway track, heavy-haul lines, crane rails and regional fastening systems. Understanding these three axes makes it much easier to specify the right clamp for a project.

Main Families of Rail Clamps

Elastic Clips for General Track

E-type clips, omega clips and tension (studded) clips are the standard elastic fasteners for railway lines. They generate their clamping force through spring deflection, hold gauge tightly, and can be installed and removed quickly with hand or hydraulic tools. Bar diameters from 13 mm to 20 mm cover light through heavy traffic.

Crane Rail Clamps

Crane clamps are heavier components designed to carry the very high concentrated wheel loads of overhead and gantry cranes. Two common models illustrate the range:

Crane clamp 21/050 AN/BN: a standard crane clamp that lets the rail be installed with good tolerances; it is adjusted to guarantee precise rail alignment and can be bolted or welded according to the end user's preference.

Crane clamp 22/130 AN/BN: a special design that secures the rail with a rubber nose; the height of the rubber nose is adjustable so that one clamp family can serve different rail sections.

Bolted Heavy-Section Clamps

Bolted clamps are high-strength clamps used with ribbed tie plates, rail bolts and washers in studded fastening systems. They are popular in regions where the fastening standard is based on bolted components, and they allow controlled, adjustable clamping force. Bolted clamps are also specified where vandalism is a concern, because they need a wrench to remove.

Regional and Special Clamps

K-type rail clamps, MTH clamps and clamps designed for North African railway practice are produced to regional standards or to the customer's drawing. These are typically customised in dimensions, material and shoulder geometry to match the local rail section and fastening system.

Installation Methods: Bolted vs. Welded vs. Elastic

Bolted clamps: held by bolts and washers; adjustable, removable, but slower to install and maintain.

Welded clamps: welded to the crane girder or baseplate; very secure, no loose parts, but removal requires cutting.

Elastic clips: held by spring force on a shoulder; fastest to install and remove, no consumables.

Typical Materials and Chemical Composition

Material	Process	Chemical Composition (%)
Q235 (forging)	Forging	C 0.12-0.20, Mn 0.30-0.70, Si <=0.3, P <=0.045, S <=0.045
ZG35 (cast steel)	Casting	C <=0.4, Mn <=0.9, Si <=0.5, P <=0.04, S <=0.04
QT500-7 (ductile iron)	Casting	C 3.60-3.80, Mn <=0.6, Si 2.50-2.90, P <=0.08, S <=0.025

Forged Q235 clamps combine strength with low cost and are the most common choice for standard crane clamps. Cast steel ZG35 is used where complex shapes are required, and QT500-7 ductile iron gives good damping and castability. For elastic clips, spring steel grades such as 60Si2MnA are used instead, because the component must flex elastically.

How to Choose a Rail Clamp

Match the clamp family to the rail type: elastic clips for railway lines, heavy-section clamps for crane rails.

Confirm the rail section and foot width so the clamp seats correctly.

Choose bolted or welded installation according to maintenance access and security needs.

Check the material against the environment: cast iron and plain steel need protection in humid and coastal sites.

For regional systems, supply the rail section drawing so the clamp can be manufactured to fit exactly.

Frequently Asked Questions

What is the difference between a rail clamp and a rail clip?

In practice the terms are used interchangeably. Strictly, a clip is an elastic spring-steel component that holds by deflection, while a clamp is a heavier, often bolted or welded component. Crane rail fastenings are usually called clamps; railway line fastenings are usually called clips.

Can crane rail clamps be used on railway lines?

Not normally. Crane clamps are designed for the wide flat head and high static loads of crane rails, while railway fastenings must hold a profiled rail against dynamic lateral forces at speed. Using the wrong family risks gauge failure and damage to the rail.

Should I choose bolted or welded crane clamps?

Bolted clamps allow adjustment and replacement and are preferred where rails are changed periodically; welded clamps give the strongest connection and are used where the rail is permanent. Some designs are supplied in both variants (AN bolted, BN welded) so the choice can be made at site.

What is the rubber nose on a 22/130 crane clamp for?

The rubber nose presses on the rail web or head and cushions the rail against lateral movement. Its height is adjustable, which lets one clamp design fit several rail sections simply by changing the nose setting.

What material is used for rail clamps?

Forged Q235, cast steel ZG35 and ductile iron QT500-7 cover most clamp applications, with spring steel (60Si2MnA etc.) reserved for elastic clips. The choice depends on whether the component is rigid (clamp) or elastic (clip) and on the load and environment.

Can clamps be made to my drawing?

Yes. K-type clamps, MTH clamps and other special designs are regularly manufactured to customer drawings. Supply the rail section, the fastening geometry and the material requirement, and the clamp can be produced and tested to match.