Rail Fastenings Systems

SD System

Achieve high performance while keeping costs low with an economical rail fastening designed to suit all track categories. Choose the Pandrol SD System rail fastening to achieve high rates of installation by mechanical methods, saving time and labour. Available in a range of configurations, highly adjustable, and suitable for retrofitting – the SD System is a versatile solution suitable for most track infrastructure.

SD System Explained

The Pandrol SD, or Safe Driven System is a pre-assembled fastening solution with controlled clip guidance, which can be easily and quickly switched from the parked to the in-service position for safe and fast installation. This threaded fastening solution is suitable for most track applications and benefits from efficient, controlled clip guidance from parked to in-service.

Despite being more economical than other captive threaded fastenings, the Pandrol SD System offers enhanced technical performance and versatility. The assembly is equally suitable for pre-assembly in the concrete sleeper manufacturing plant and for retrofitting to sleepers with other fastenings on existing track infrastructure.

  • A pre-assembled fastening solution for easy, safe, and quick installation
  • Compatible with both manual and mechanical installation methods
  • The Pandrol SD System was selected over other threaded fastenings for the prestigious Grand Paris in France and Tren Maya projects in Mexico

Advantages of SD System



Achieve very high rates of track maintenance and construction with the help of the SD System’s simple ‘switch-on/switch-off’ function, and the option of using mechanised equipment to speed up installation. The SD System is delivered to your site pre-assembled, reducing labour, handling and distribution costs during the system’s lifecycle.



Choose a fastening system configured to your rail project’s exact requirements. The SD fastening is adaptable to suit a wide range of parameters including stiffness, adjustment, and rail clamping force, so you can be sure of optimal performance in all environments. The system is even suitable for retrofitting as it can be installed in an SKL-shaped rail seat. Simply change the guide plate insulators in the required increments to achieve accurate lateral rail adjustment.


Compact design

Rest assured that the SD Fastening System is the only rail fastening system you’ll need for the entirety of your rail project. The SD clip is specially designed to be compatible with even the smallest of spaces, including turnouts. It is suitable for use throughout the entire length of the track, regardless of changing space availability.


Environmentally friendly

Select a fastening system with environmental impact in mind. The SD System clip is relatively low in weight compared to similar products. When combined with its nature as a pre-assembled captive unit that is quick and not labour-intensive to install, the SD System’s environmental impact is smaller than alternative products, without compromising performance.

Technical features of the SD System



Save time and labour with the SD System. SD sleepers are usually supplied to the track construction site as captive, fully pre-assembled units, reducing the need for manual intervention onsite. All components in the assembly also remain captive during construction and maintenance activities, which can contribute to enhanced safety.


‘Switch-on/switch-off’ function

Move the SD clip simply and quickly from the ‘parked’ position – in which it is held securely without intruding into the rail seat – into the ‘service’ position. Once the screw is loosened, the clip can be manually pushed from one position to the other to either clamp or release the rail with very little effort and without the need for hand tools.


Clamping force

Preserve the safety and longevity of your rail system by preventing vertical and longitudinal movement of tracks with Pandrol’s SD System. The high elasticity of the SD clip ensures the correct clamping force. Consequently, a consistent longitudinal restraint is achieved automatically when screws are tightened until full contact is made.


ZLR configuration

Deal with track-structure interaction with the SD System rail fastening assembly. The SD’s clips are available in low toe load and zero longitudinal restraint (ZLR) configurations – ideal for safe and reliable installation on bridges and viaducts.

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