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Monday, August 13, 2018

New NORAC Signal Rules!

Yes, and before people get all nit picky yes NORAC is indeed adopting both new rules and a couple new aspects that go along with old rules.  All of the new changes have in fact been used for many years by a number of member railroads as system special instructions and moreover they have also been seen in other railroad signaling systems.  This is a nice example of a signal rules committee looking at the state of the art and deciding not to keep its head buried in the ground.

The new rules were made effective in the 11th edition of the NORAC Rule book released on Feburary 1, 2018. I've been a bit busy since the start of the year so I just hadn't noticed until now XD


We begin with Rule 281a, Cab Speed, which has been modified to include SEPTA's *G*/*G* dwarf indication which it has been using for about the last 10 years.  Also included was a PRR pedestal indication probably because of some situation on Amtrak.


 The next change plugs a major hole in several eastern signal aspect systems in that there is often no Approach indication available on dwarf signals. Y/R is Slow Approach, Y is restricting and for years NORAC had to make up with displaying Y/*R* Medium Approach for straight routes.  However there was one obvious solution and after appearing on the Conrail SAA timetable as a special instruction for years, *Y*/R has been adopted as Approach.  CSX please take notice.



A bit more consequential is the long overdue adoption of Medium Approach Slow.  Unlike CSX which had reserved R/Y/G for M-A-S forcing R/Y/*G* for M-A-M, NORAC went with a nod to the PRR using R/Y/Y.  This aspect had long been used in by the MBTA in the Boston area and possibly also on the former Boston and Maine territory. More recently it had been incorporated into Caltrains new speed signaling system in 2003. Note, NORAC Rule 283b does not include the "when first becomes visible" admonition, which I would suspect is something they are trying to get away from.


Finally in a weird nod to the Seaboard Coast Line, NORAC has adopted Limited Approach  signal as Rule 286a.  However, unlike the CSX Rulebook which is a bit ambiguous about when a train must slow to Medium Speed, NORAC Rule 286a states that Limited Speed applies only through the switches and turnouts, then Medium Speed applies.  Like Rule 286 Medium Approach, trains must begin reduction to Limited Speed as soon as it becomes visible.  I suspect this might be used to claw back a few seconds where trains had previously been stuck at Medium Speed due to a far-yet-visible Medium Approach indication.

All in all these are sensible moved by NORAC.  The real question continues to be when CSX will finally adopt *Y* Advance Approach!!

3 comments:

  1. Replies
    1. I was wondering about that but wasn't sure. Thanks for pointing it out.

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    2. Oh, I actually mentioned it in the text, but didn't have time to re-edit the image.

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