Version 0.51 Briefing Note

The sections below detail enhancements that will be deployed to aSIST on Sunday 25 April 2021.

Notification of Weekly Disruption

Following the Version 0.51 upgrade, the system will now automatically restart each week, Sunday 0300hrs.

This is to reload any frozen sessions.

A verbal alert will sound informing users to follow on screen instructions to reactivate.

User Interface Enhancements

Silent Alarm Option

A silent alarm (visual alarm, but not audible) option has been introduced for any signals that require routing info only with no audible alarm.

This prevents the audible wrong route alarm sounding when trains are diverted off the booked line when they can get to the same destination, but the system supplies booked line details for signaller info. For example, where fast and slow lines run parallel and lead to the same destination, but trains are regularly routed onto the non-booked line for either regulating or because of regular track patrols

The visual wrong route alert will display, but no wrong route will be recorded.

This is similar to the "mute" function, but is permanent within the location set up.

Delayed Data Message

The system now checks globally for data updates before displaying the message that no data is being received.

Previously only that singular train describer was checked meaning the message would display frequently in quieter areas

System Back-end Enhancements

Version Control

In the back-end the system will send data (list of trains approaching, routes set etc) every two seconds.

The system will then do a version control check for that data, and auto-reload if the version is old. This ensures all data is up to date and allows automatic roll out of new versions without user intervention.

Route Refresh when Data Out of Sync

The data tolerance has been amended to prevent the TD and s-class (signalling) data becoming out of sync.

Previously, the signalling data could become out of sync, for example a signal placed at danger or route set but the system would not receive this data until 15s later.

This risked a false wrong route alarm being generated for a following train, because the system thought the previous route applied to it.

The system now has just a 10s tolerance so will reset all signalling data if it becomes 10s out of sync with the train describer.

Users should be aware that following a reset and to mitigate a false alarm as described above, the correct route will be shown to the user but the wrong route alarm will not be activated if a wrong route is set. This will be the case until a new route is set.

Note: This enhancement has been introduced following a major Network Rail IT issue that affected data feeds. However, this is a rare event and the feeds have since been stable.