Still baffles me how packed the old system was with failure modes, though.
If a train finds itself on a segment it has not been authorized for, it stops - regardless of what the driver thinks of the matter.
Controllers can’t then give authorisation to another train to enter that section, nor can they override any red signal. In cases where it applies, they also can’t remotely control track switches to enter this occupied section. However there’s nothing with that system that then controls the rolling stock itself, so a driver can still SPAD if they don’t see or ignore the red, and the remote network controller absolutely cannot stop a train that is hurtling towards an occupied section. That’s all on the driver in the cab.
Fun fact: track clips are used by track gangs to short these sections in lieu of a big axle sitting on it, which is one of the methods of providing site control to the gangs so trains don’t enter their worksite. It’s certainly not the only one, though.
All trains have instrumentation which will cause them to stop if they pass a red signal.
The gritty details appear to be in the Togframføringsforskriften, however this has been repealed a couple of years ago, presumably to bring us in line with EU regulations - but I am too tired to try to figure this out tonight, though I have always been a sucker for figuring out how signalling systems work...
Not all trains have kit to stop a SPAD, unless you meant specifically in the instance of the operator involved in this incident. Some do, but it’s absolutely not universal around the world. For example, Automatic Train Protection (ATP) can do this, but it requires both a track-side magnet and the rolling stock to have the kit for it. We use that to trigger our driver vigilance system acknowledgement when approaching suburban passenger stations. Failure to acknowledge the vigilance prompt will throw the brake to emergency and stop the train.
That said, it’s absolutely not present out in the Wild West of freight (because maintaining that many ATP magnets is insanely prohibitive).
Box-to-train emergency communication was itself definitely a solved problem by the mid 20th century, though...
Long, crushing silence, then. "Presumably, yes."
If I remember correctly, one of the key findings after the accident was that train controllers' only means of communicating with the trains they were supervising was to call the train drivers. On their personal cell phones. It was part of the procedure prior to starting a journey to call in to the central and have the controllers write down the phone number to be used to reach, say, the southbound from Trondheim.
Now we luckily have modern train management systems and GSM-R, but 19 people died at Åsta because the northbound driver seemingly forgot that there was a southbound train on incoming on the track he was going to use - and didn't pay attention to the signal telling him the track was occupied. Then, once the northbound train got going, train control took a couple of minutes to figure out what had happened and then also found out that he couldn't find the note with today's phone numbers.