Track Forces in a Switch


Deformation measurements to determine mechanical forces in a railroad switch of Ofotbanen


Lateral forces excerted by iron ore trains on a guard rail of a switch are determined on the diverging track of a railroad switch at the entrance to Narvik. Strain gauges are attached to brackets supporting the guard rail and measurements are converted to stresses using finite element modeling (FEM). The aim of this project is to obtain a record of stresses resulting from a range of axle loads, train speeds, and environmental conditions. This NORJETS project started in fall of 2018 and is financed by Bane NOR. It follows a pilot study in fall 2017.

Project contact: Rune Nilsen, Norut Narvik.

Straing Gauge Installation

Strain gauge installation, photo: R. Nilsen


Data on this page are for the current calendar year. For older data see:

  • 2020 data of the current installation are here.
  • 2019 data of the current installation are here.
  • Archived data of the installation of fall 2018 are available here.
Two brackets had been replaced on 7 July 2020, approx. 7 UTC and channel order has been since (Kiruna to Narvik): Ch 1, 2, 3, 4, 6, 5, 8, 7.
Sensors of channels 3 and 4 began to detach in the middle of November 2020. Hence, the trigger channel was changed from Channel 3 to Channel 7 on 7 Jan 2021.

Plots are generated automatically for illustration only and updated every 15 to 30 minutes. Neither plots nor information displayed on the plots are quality controlled. They may not be correct. "Correct" raw data (i.e., voltage ratios of the the full bridge circuit) are available in the data file linked below each plot.

Note that each plot starts with all strains at zero as a result of a processing choice. Manual evaluation of each train passage event is advised.

The last completed event was number 16145 (2021/03/30 06:00 UTC), the logger supply voltage is 11.08 V (2021/03/30 06:00 UTC).

Battery Voltage Plot

Recent Battery Voltage

Heavy haul events include iron ore trains with loaded F050 wagons (LKAB, Bottom Dumpers) , and iron ore trains with loaded F121 wagons (Kaunis Iron, Helix Dumpers) 11592.