Pennsylvania NS Derailment

[Euclid]

Sometimes the obstruction is a train, but other times, it is just an obstruction of the view, such as a curve.  But even on straight track and no obstructing train, there is another form of obstruction, which is just the human vision limit of a person’s ability to assimilate and identify a distant object. 

 

For the curve obstruction, the “half speed” component is constantly decreasing as the train moves forward.  If operating toward a curve at maximum permissible speed of “Restricted Speed,” each increment of distance has to be traveled at a lower speed than the previous increment.

 

But with straight track, the proper restricted speed can be constant as long as no obstruction is seen.     

[jeffhergert]

Overmod

If anything, I was the one who came closest to 'trying to rewrite the rule' -- in saying that if the rule reads clearly 'half the distance to the obstruction'  any testing for it ought to enforce compliance.

The actual rule for 'restricted speed' was part of the same ICC Order of 1947 that imposed the train control/continuous cab signal requirement in the early Fifties.  And both its text and its discussion in the Federal Register clearly state 'stop short of an obstruction' -- which is, of course, how all the railroaders see it being tested.

I encourage anyone to go to the link I posted and read the discussion and text of the Order for themself.  Any hypotheticals that involve that definition should be fairly clear to address afterward.  All that has apparently 'changed' is that the rule now says 'half the distance' just in case the 'obstruction' happens to be a train moving at restricted speed.  And all that remains is to find the "official" time and place that the rule was modified to read as it does... together with, I suspect, the then Government rationale for imposing it (and, hopefully, some insight into how rear-world humans could properly execute it as written).

 

Restricted speed was not a rule until sometime in the 1990s the best I can tell.  The General Code of Operating Rules, third edition from 1994 is the first GCOR to have it as a rule.  The previous two GCORs, and a Conrail 1985 rule book I have, and all other rule books previous, show Restricted Speed as a definition. 

The wording about operating at a speed allowing stopping within half the distance was added sometime in the 1980s.  The 1980 edition of the Consolidated Code, and rule books I have earlier than this date, don't have the wording.  The first GCOR (1985) and the Conrail book do have the wording in the definition.

My personal belief is that the wording, "half the distance," was added to emphasize that restricted speed was not to be construed as a constant speed.  Rather, it needed to be modified as conditions (sight distance) dictated.

Jeff

 

[BaltACD]

The B&O Rule book I got when I hired out was published April 26, 1953 and reprinted with updates to December 2. 1964. It defines three speeds -

Medium Speed - A speed not exceeding thirty (30) Miles Per Hour
Slow Speed - A speed not exceeding fifteen (15) Miles Per Hour
Restricted Speed - Proceed, prepared to stop short of: train, obstruction, improperly lined switch or broken rail

Restricted speed is not defined by MPH and there is no mention of 1/2 the range of vision.