Following the fatal Buizingen crash in 2009 the entire rail network was equipped with TBL1+. The system stops trains automatically if a driver ignores a signal at red.
Infrabel, the rail track operator, has been unable to confirm or deny the report. Rail track spokesman Frédéric Petit: "At the explicit request of the public prosecutor we are not providing information about the investigation or elements of the investigation. We cannot say anything about the signal."
Infrabel stresses that 7,500 of Belgium's 10,700 rail signals have been equipped with the latest technology covering 99.9% of the network.
The company states: "The actual coverage of this system was determined using objective criteria that were used to calculate the theoretical risk."
This means that the number of passengers and trains using the line and train speeds are taken into account.
The investigation into the crash in which three people were killed continues. On Tuesday the train's black box that records all movements was recovered.