Train brakes back-up alert
The Federal rail safety regulator has issued an urgent alert over heavy freight trains after the spectacular derailment of a BHP iron ore train in the Pilbara, warning of “serious safety concerns” over some electronic brakes.
In a notice to train operators around the country, the National Rail Safety Regulator has ordered companies to carry out immediate checks of trains that use electronically controlled pneumatic braking, saying initial inquiries into the BHP incident have revealed potential safety issues over a fail-safe for the system.
BHP has given only the barest of details of the November 5 episode when the company was forced to deliberately derail a 258-car runaway ore train after the driver stepped off it to do an inspection.
BHP said the train came to a stop after a braking system control cable became disconnected and when the driver got off, an emergency air brake was not engaged.
It said the electric braking system that initially stopped the train automatically released after an hour while the driver was still outside, but because of an “integration failure”, the back-up system did not deploy.
The train hurtled uncontrolled for 90km at speeds of more than 100km/h before it was run through a siding south of Port Hedland and derailed.
The rail safety regulator said investigators had discovered a potential issue with a system called Automatic Train Protection, which is supposed to provide a back-up to ECP braking.
It said the trains had a software feature to preserve battery life on ECP-fitted wagons where the electronic brakes are released in some circumstances — including when there has been no input to the system for 60 minutes.
“Where these conditions exist, the ECP braking system will release, creating the risk of a rollaway incident unless the air pressure within the system has been released to atmosphere,” the alert says.
The regulator said it had found in the event of a roll-away and the failure of the ECP system, the ATP system did not fall back on the mechanical pneumatic system.
The alert orders all operators to check whether the 60-minute release system has been programmed into their ECP braking software.
Train operators have been told to conduct a risk assessment of the effectiveness of the ATP if there is an ECP braking failure.