Well apart from the 'train long time in section' rules. Trains being a long time in section invokes SGI 22
If an unusually long time passes after a train has entered a
section, you must try to contact the driver to find out the cause. If
necessary, you must arrange for Operations Control to do this.
• stop each train on any adjacent line travelling towards the
overdue train
• tell the driver of each train the circumstances regarding the
overdue train
• instruct the driver, that when the signal is cleared, to proceed at
caution and to be prepared to stop short of any obstruction
• tell the driver to report what has happened with the overdue train
• signal each train normally.
The only time I can see a DOO train being dangerous is if:
There is a derailment where the driver is killed/badly injured and does not hit emergency on his DOO (most would approaching an obstruction). No passenger or onboard staff ring 999 or contact their operations control AND the train is fouling an adjacent line and has not destroyed lineside equipment or shunted track circuits AND this in happens in a very short time frame as to not to invoke SGI22.
I would further add it's not just signalling staff that watch the progress of trains: TOC and NR control also do and have indications showing trains long time in sections, as do many managers, station staff and so on. Trains long time in section often result in calls to the controlling signal box.
Guards are normally employed on absolute block line in any case. In which case track circuit clips are useless and they must run braking distance (over 1 mile, which would take at least 5-10 minutes at best) in order to place emergency detonator protection assuming they cannot contact their operations control/or signalling.
This is why I find this idea of taking away safety critical staff a red herring. Unless you have a deep understanding of railway operations (most people do not) its an easy accusation to make that somehow there is a big safety issue.
The reality is, even non-safety critical (which means staff unable to go on the lineside and use track circuit clips/place detonator protection) would ring 999/their ops control, do what they could anyway to stop approaching trains. Even IF all that fails AND SGI 22 is not invoked the chances of a major mishap are minuscule, and other mishaps such as level crossings or vandalism pose a far greater safety risk.
Most of the fretting is unions trying to protect jobs (fair enough) or drivers that do not have as complete understanding as they think they do - which is actually surprising common. It is a complete mystery to most of them what goes on inside signalling centres/ops control, nor do they have any understanding of the signalling regulations as they are not taught them or get involved with them.
Another question though... there are sections of line where the signalling is operated by axle counters rather than track circuits, are there not? In these situations, how does one protect an adjoining line? Or are TC's still used and the axle counters are there as the primary means of signal actuation?
GSM mobile phones/lineside phones/full detonator protection/NRN. Same as on Absolute block lines.