> Regarding the red signal being discussed: I note a significant number of people here
> have called this signal restricting, restrictive, stop, and red over flashing red
> and have used insinuations in their posts that a stop should have been made.


I will take OPRRMS's word for it that the signal was red over red (stop). He is usually accurate.

However, at the time of my post, it was still being reported as restricting. So I answered the question about how the PTS will operate with such aspects; how the PTS will have to require a stop and proceed. This is in order to make sure a call-on aspect is actually being respected, before PTS allows entry into an occupied or fouled block - which it must allow as per the aspect.

In the old days, many roads did require a stop and proceed at a restricting aspect, though that requirement seems to have been relaxed over the years. But it may have to be re-imposed for PTS to safely handle the restrictive aspect.

At the existing state of the art, the primary task of PTS is to enforce signal aspects. But it will still be relying upon coded track circuits to assure a clear track ahead, and also to accurately determine which track a given engine is on. This is because PTS technology can itself safely and reliably detect neither the track nor the exact position on that track of ALL obstructions. And it cannot detect the presence of many obstructions at all (such as unequipped freight cars) without the track circuit. But track circuits are not very good at determining the exact location of anything - just its presence or non-presence.

Therefore, the initial stop at the restricting signal must be enforced by PTS, followed by a mode change by the engineer to override the enforced stop. But still, after the stop and mode change, for the foreseeable future, PTS will be of little help while running on the restricting aspect. It can only stop a train before it enters the fouled block - not before hitting something or somethings it cannot accurately "see" inside the block.

That is the best it will do for now - for years to come actually, as the technology to do better has not been even conceived of yet. That is my opinion after thousands of hours involvement in government sponsored test projects, using various radio ranging technologies to control trains, such as GPS and CBTC.


So, for the benefit of anyone on this forum thinking that They burst my bubble about PTS, it actually was burst years ago, by practical experience with such technologies. For the foreseeable future, it will be of marginal benefit at best (but at extreme cost) - and it will not prevent all signal violation accidents either. Some yes - all? H--- No!

What still needs bursting though, is the bubbles of bubble-headed politicians and lobbyists that think they know so muckin futch about which technologies work and which don't. And while were at it, lets burst the bubble of the railroad supplier that bought and paid for those bubble-headed politicians in the first place! They are no friend of railroads - nor of railroaders.

OPB