The reporter has raised a safety concern relating to the incorrect information provided by the Rail Traffic Overview Application (RTOA) database display following a signal passed at danger (SPAD) incident at the [Location 1] yard, [State].
The reporter states that on [date], [Operator 1] train [train 1] passed signal [signal 1] at red while travelling west through [Location 1] yard. However, the RTOA database that shows the location of trains on the [Operator 2] network, shows this train stopped at signal [signal 1] and [Operator 2] train [train 2] out on section.
The reporter states this discrepancy was raised with [Operator 2] network and was subsequently advised that this is not abnormal and that staff should not be concerned. The reporter further states the incident was reported to the rail regulator who advised they were unable to disclose any information outlining any action that may or may not be taken.
The reporter states this incident has occurred in the past and is concerned that critical safety information resulting from an incorrect RTOA display is not being passed to train drivers resulting in an unsafe work environment.
Is [Operator 2] network able to explain why a SPAD alarm did not activate under these conditions when train [train 1] exceeded its limit of authority by passing signal [signal 1]?
Operator 2] acknowledges the reporter’s concerns and provides a response on each element below.
[Operator 2] would like to advise the RTOA system is not a safe working system, it is an information system only. The RTOA is a separate system to the Universal Traffic Control (UTC) system, which is utilised by Network Controllers for the safe management of rail traffic. This is made clear to users in a banner across the top of the system, as shown (image supplied to the ATSB and ONRSR).
In relation to the event at [Location 1], on [date], referred to in the REPCON, [Operator 2] provides some additional detail below. Please note these are extracts from the UTC System, not RTOA.
UTC Prior to Proceed Authority Exceedance (PAE) (image supplied to the ATSB and ONRSR)
Trains [Train 1] and [Train 2] were positioned on the approach side of [signal 1] and [signal 2] respectively, as shown in the diagram (supplied to the ATSB and ONRSR). [Train 1] reads across to the left and proceeds on identification of the wrong signal ([signal 2] which was set at proceed for [Train 2]). While investigations are ongoing, this is what [Operator 2] believes to be the direct cause of the PAE.
UTC Alarm Messages (image supplied to the ATSB and ONRSR)
As train [Train 1] continues through [number] points, a yellow warning alarm is generated on the Network Controller’s UTC workstation. As per [Operator 2] Network’s safe working rules, this requires the Network Controller to acknowledge the alarm and investigate the cause, and through this investigation the PAE was identified and emergency response procedures enacted. It is important to note UTC alarms and messages are not available through RTOA.
In relation to the question about PAE alarm activation, due to the design of track circuitry, there are some circumstances in [Operator 2]'s [Location 2] Network where two trains await authority onto a single converging track circuit. If either of those trains has authority the systems expect the track circuit to be occupied. If a train then exceeds its authority into this track circuit, the system has no way of differentiating which service has occupied it and is designed to update showing the train with authority has taken its intended route. Once the circuit is occupied, the system will restore the signal that was initially showing a proceed authority to stop.
In more complex situations, [Operator 2] also considers additional situational awareness tools. For example, the gantry mounted signals at [Location 1] are fitted with arrow signage to reinforce the road to which each signal applies. The gantry layout of the [Location 1] signals in question, showing directional arrows is shown in the picture (supplied to the ATSB and ONRSR).
[Operator 2] has previously discussed converging track circuits at operator forums and commits to generating ongoing awareness of this system design, and the correct use of the RTOA application, also through regular forums and engagement with Operators.
ONRSR confirms receiving ATSB REPCON report number RR2023-00035, regarding discrepancies in the Rail Traffic Overview Application display. The ONRSR review of the reporter’s concerns and operator’s response included a review by a technical specialist. Regarding the concerns raised in the REPCON report, ONRSR is satisfied with the operator’s response.