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RTG RMG weighing system

CWS, an automated weighing system for RTGs, enabling ports to automate the VGM process, increase efficiency and maximise terminal revenue.

CWS™ has been designed specifically for RTG’s and RMG’s to provide a highly accurate VGM container weighing system that give the ability to measure the weight of a lifted container in real-time within 1 percent full-scale accuracy.

CWS is available retrofit or as a factory-fit option for new machines and can be installed into all major manufacturers of spreaders and cranes (RTGs, RMGs, ARMGs and CRMGs). JF Strainstall’s CWS™ utilises JF Strainstall’s proven load monitoring technology to provide a reliable and highly efficient method to obtain VGM data, providing a more efficient, integrated and automated method for producing a verified gross mass (VGM) versus a traditional weighbridge.

By utilising RTGs and stacking cranes to capture VGMs as part of the existing lifting and stacking cycle, ports can reduce their dependency on weighbridges, process more containers in the same time, and, reduce the point of failure from a single weighbridge across an entire fleet of RTGs.

Weighing in motion

The advanced algorithms JF Strainstall have developed allowing the stable weight to be captured during lifting, without the need to stop to take a holding weight.


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Automatic operation

Unlike the majority of other systems available, CWS by design captures the VGM automatically using our in-house developed algorithms without operator interaction and can integrate into existing TOS systems.


Automatic operations

Increased revenue for terminal

By removing this process entirely with a substantial more efficient method, terminals can now implement a new weight validation service that can be charged for as an additional revenue source for the terminal.




Significantly faster method of VGM capture

As VGMs are captured as they are lifted in real-time during stacking operations, removing the need to be weighed on a weighbridge and re-weighed to determine the tare weight.


Proven track record

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How does the CWS system for RTGs / RMGs work?

CWS uses JF Strainstall’s proven load monitoring pins or diaphragm (annular) load cells depending on machine configuration that replace existing load bearing pins or twist lock collars in order to capture the VGM (verified gross mass) of a container. The four load cells are connected via a wired CanBus connection to an interface unit (mounted on the spreader) to aggregate data.

The interface unit then connects to an in-cab display using either a wired or a wireless connection to the in-cab display that provides the operator with a view of the current load, the holding weight, as well as identifying eccentrically loaded containers.

CWS as standard is also able to integrate with Terminal Operating Systems (TOS) via Ethernet (standard), serial output (RS 232/422/485) or CanBus. Data output includes the container’s VGM, load eccentricity and the date/time stamp of the VGM.


Read more about our CWS™ systems




Case studies

Yilport Ferrol

JF Strainstall's Container Weighing System (CWS) triples container weighing speed for Yilport Ferrol

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Flavio terminal

Flavio terminal, Naples is equipped with SOLAS compliant reach stackers from JF Strainstall and Kalmar

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DP world

Container Weight System (CWS) installed on to all DP World straddle carriers in Southampton

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Container Weight System brochure


Container weight verification

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