> Did I miss something?


No you didn't - technically. I went back and double checked.

I blurred the subtle distinctions between two different FRA actions. The emergency order itself applied only to Metro-North. However, the FRA subsequently issued an "Industry Wide Safety Advisory" (FRA's words) that in the aggregate implicated traditional world wide signal designs and operating practices, as a contributing factor in this accident; and among other things required that all railroads review their own operating practices, methodologies, and such, with all their employees; in light of what is now known about the Spuyten Duyvil accident.

I say "subtle distinction" because their net bottom line effect on the practice of railway signal engineering can be nearly identical. Since you already have other commuter railroads voluntarily complying with the gist of the EO, and a federal mandate on at least one railroad to comply or else; it will now be very hard for any professional railroad signal engineer to resist applying this new standard as the "Current Industry Standard Practice".

But don't get me wrong - the officers of the company that those signal engineers must report to, will continue to resist as long as they can. "Safety First" is just jaw flapping - what is real is "Bottom Line First". Can an industry wide order be far behind if they do not allow compliance - NO!

What you may not know, is that the net effect of ignoring this notion of "industry standard practice" can get your PE license revoked, should your out-of-adherence signal designs get someone killed. More compelling yet, once a given design practice is known to any signal engineer or company officer as hazardous (as it now is because of the Spuyten Duyvil safety advisory); they can be held civilly and criminally liable if their non-compliance with industry best practices, leads to injury or death.

While an FRA Emergency Order could be considered as a heavy hammer; a safety advisory could also be viewed by the professional engineer as a runaway steam roller. Dodging it can get dicey indeed - hence the distinction between an emergency order and a safety advisory is blurred in my mind.



As to the primary weakness in existing ACS/ATC systems that is at issue world wide in this case; it is simply this. That the same signal aspect (cab or wayside) can require different actions depending upon the specific track parameters at different locations. This leads to the problem of the signal system not being able to safely control train speed approaching curves or other hazardous conditions; even with continuous inductive automatic train control.

It seems that everyone is so shocked by these accidents, "How can that happen" is exclaimed so plaintively, each time. It is because those signal systems have come to be so relied upon by all (world wide) to prevent human error from causing accidents, that human guard has been let down. But it is now known that signal systems must now actually do that - or else accidents are inevitable.

The fact that in the past, the design focus was only upon preventing collision, and that other hazards were ignored, has been long forgotten. Well, the safety advisory requires that all be reminded. But its net effect on signal system design, will be a de-facto requirement to cover this hazard in all future designs and retrofits.


But that really is no big deal. The EO's requirements are quite reasonable, and relatively simple and inexpensive to complete. All that is required, is to re-arrange signal controls in approach to all fixed speed restrictions that require a significant speed change, so that the inductive cab signal picked off the rails, reflects actual track conditions ahead. Recall that this is already done at interlockings, to reflect dynamic speed restrictions over the track switches. Well, now it would also be done to reflect fixed restrictions, as is now already done on several rapid transit lines and at least one US commuter railroad (UTA Frontrunner).

Note that continuous control pver all types of speed restriction is already a part of the A.R.E.M.A. PTC specification. Note also, that it is becoming increasingly likely, that this spec (and the spirit of the law) will be met by applying just these sorts of changes to existing coded track circuit systems (most modern installations), and by installing onboard equipment to at least enforce speed limits and supervise mandatory braking in a more sophisticated way. So the above mentioned fix is already in the works anyhow, one way or another

Hope that explains it all.

OPB