Since the beginning of the year, Väte Trafik has been handling the shunting of SSAB’s steel trains in Borlänge and Oxelösund. This is Väte Trafik’s largest assignment to date, and four fully modernized SM42-6Dg locomotives have been leased to carry out the work. Railway Metrics and Dynamics is now equipping the locomotives with PMUs and smart bolts.

RMD Developing Fully Approved System

The locomotives are currently used exclusively for shunting, but there is also interest in getting them approved for mainline operations. To enable that, improved hotbox detection is needed for the wheel axle bearings.

The bearing housings will therefore be fitted with smart bolts from RMD’s partner, Strainlabs. Some of the original bolts in the housings will simply be replaced with new bolts equipped with built-in temperature sensors.

The temperature data is transmitted to a PMU (Performance Monitoring Unit) mounted on the locomotive. The data from the PMU is processed by RMD’s system platform – which can then forward compiled temperature information to any desired system.

– We’ve already received confirmation that this is a fully compliant solution for hotbox detection, which is very promising for the future, says Jan Lindqvist, CEO of Railway Metrics and Dynamics.

Another System-Within-a-System Solution

As part of this assignment, RMD is also providing a simplified version of its comprehensive MyTrain application, which visualizes the information in a graphical interface for the train driver.

– RMD provides a mini-system for hotbox detection that any of our freight operators can purchase, says Jan Lindqvist.

Each of the locomotives leased to SSAB will be equipped with both PMUs and smart bolts. The lease agreement for the technology, system, and app is open-ended.

This delivery is part of the existing agreement with Väte, valued at SEK 974,550 per year over a three-year period.

The new hotbox detection system is scheduled to be operational at the beginning of August 2025.