Reuters reported rail line owner Fenoco as saying Monday that the trains had crashed at the Guamachito station in Magdelena department, causing a derailment that overturned three locomotives and 23 cars. Twenty of those cars were loaded.

Officials are investigating the cause of the incident, which occurred at about 10.55pm local time April 3. However, local outlet Colombia Reports said Monday that authorities were blaming the crash on a breakdown of communication relating to the two trains' handling, which ended in both travelling on the same line but in opposite directions.

Fenoco’s shareholders include Glencore’s Prodeco unit, Drummond Coal, Vale and the Colombian unit of Goldman Sachs. Neither the rail line nor Reuters identified the owners of the coal or the trains’ destinations.

The railway operates about 24 trains daily from the mines in the northern region of the South American country to Atlantic ports.

Colombia is the world’s fifth-largest exporter of coal.