Rule 562 and SEPTA trains?

[h***@bbs.cpcn.com]

DVARP came out against "Rule 562" signalling:

"DVARP has serious concerns about the impact of SEPTA’s recent
resignaling projects. In some instances, they have led to slower
service speeds by ‘dumbing down’ the system, and have been sharply
criticized by operating personnel.. What is best for a rapid transit
line is not necessarily best for a commuter railroad, so SEPTA should
not force rapid transit signal systems onto a commuter railroad . . ."
http://www.dvarp.org/documents/FY09CB.pdf

Anyway, could someone elaborate on what '562" signals are and why they
are a detriment to service? Also, elaborate on the SEPTA signal
situation"?

Thanks. public replies please

[Jishnu Mukerji]

Rule 562 refers to NORAC Rule 562 which addresses the use of cab
signals. Take a look at:

http://www.svmetro.com/septawatch/signals/rule-562.php

I have no clue what DVARP is bitching about. Since Amtrak uses Rule 562
all over the NEC I find the characterization of using Rule 562 as for
"rapid transit" somewhat amusing to say the least.

It is true that cab signals as found in the NEC area based on the old
PRR design tends to slow operations down because the cab signal shows
the signal that was just passed and the speed is enforced based on that
even if the next signal is miles away, rather than the signal that is
being faced. But as discussed at length on this newsgroup by Greg and
others given the technology that was available back then there was no
practical means of doing anything useful with the info about signal
being faced since the distance to said signal was not passed to the
train and even if it was the train probably would not have been able to
make good use of the info given the state of electronics that was
available back then, though perhaps the engineer could, but then it
would not be automatic speed control.

Perhaps this unfortunate feature of cab signals is what upsets DVARP,
but I have no way of knowing for sure, since they also conflate the
issue of some accident which I am not fully familiar with, though I find
it hard to believe that Rule 562 caused such to happen. But not knowing
the details I will withhold judgment on that.

Post by h***@bbs.cpcn.com
"DVARP has serious concerns about the impact of SEPTA’s recent
resignaling projects. In some instances, they have led to slower
service speeds by ‘dumbing down’ the system, and have been sharply
criticized by operating personnel.. What is best for a rapid transit
line is not necessarily best for a commuter railroad, so SEPTA should
not force rapid transit signal systems onto a commuter railroad . . ."
http://www.dvarp.org/documents/FY09CB.pdf
Anyway, could someone elaborate on what '562" signals are and why they
are a detriment to service? Also, elaborate on the SEPTA signal
situation"?
Thanks. public replies please

[Stephen Sprunk]

...

Post by h***@bbs.cpcn.com
Anyway, could someone elaborate on what '562" signals are and why
they are a detriment to service? Also, elaborate on the SEPTA signal
situation"?

Rule 562, as I found out with about 30 seconds of Googling, is use of cab
signals without wayside signals except at interlockings.

The idea is fine. The problem is that PRR signals show the (invisible)
signal the train just passed, so when a speed reduction is required, the
engineer has to immediately put in enough braking to suppress a penalty --
something he would have already done if he'd been able to see the signal
before he passed it. This will naturally lead to twitchy engineers, lower
speeds than the signals allow, frequent penalties, delays (and perhaps
snowball penalties) for the train behind the penalized train, etc.

If a real cab signal system (e.g. TVM, LZB, ETCS, etc.) were in use, there
would be no problem at all because the engineer would see speed reductions
_before_ he reached them, allowing smoother and safer braking while running
at higher speeds and closer spacing.

Why DVARP refers to this as a "rapid transit" rule is a mystery to me, since
this rule originated at Amtrak when they started ripping out non-home
wayside signals on the NEC. Non-FRA systems use more advanced cab signals
or none at all (either way, not the PRR system) and thus have no need for
it.

Also, apparently the reason this is such a big problem for SEPTA, whereas it
apparently wasn't for Amtrak, is that SEPTA also lengthened the blocks vs.
the old ABS system as part of the same project...

S

[h***@bbs.cpcn.com]

Post by Stephen Sprunk
Why DVARP refers to this as a "rapid transit" rule is a mystery to me, since
this rule originated at Amtrak when they started ripping out non-home
wayside signals on the NEC.  Non-FRA systems use more advanced cab signals
or none at all (either way, not the PRR system) and thus have no need for
it.
Also, apparently the reason this is such a big problem for SEPTA, whereas it
apparently wasn't for Amtrak, is that SEPTA also lengthened the blocks vs.
the old ABS system as part of the same project...

SEPTA might have used this approach on _new_ applications on rebuilt
tracks that didn't have cab signals at all, only wayside (such as the
Reading side).

What's puzzling is why would they _remove_ wayside signals? The PRR
style cab signal is meant as a safety backup, not as a replacement for
the operational reasons you describe.

[Art Clemons]

What's puzzling is why would they remove wayside signals?  The PRR
style cab signal is meant as a safety backup, not as a replacement for
the operational reasons you describe.

No, it's not meant as a safety backup.
Septa is a full Norac member, meaning that its engines all are supposed to
have Norac signaling capability. In fact, the cab signals are the main
signals supposedly.


http://broadway.pennsyrr.com/Rail/Signal/aspects_us_norac.html
http://www.svmetro.com/septawatch/signals/
http://www.svmetro.com/septawatch/signals/rule-562.php
http://www.trains.com/trn/default.aspx?c=a&id=230

[Stephen Sprunk]

Post by h***@bbs.cpcn.com

Post by Stephen Sprunk
Why DVARP refers to this as a "rapid transit" rule is a mystery to
me, since this rule originated at Amtrak when they started ripping
out non-home wayside signals on the NEC. Non-FRA systems use
more advanced cab signals or none at all (either way, not the PRR
system) and thus have no need for it.
Also, apparently the reason this is such a big problem for SEPTA,
whereas it apparently wasn't for Amtrak, is that SEPTA also
lengthened the blocks vs. the old ABS system as part of the same
project...

SEPTA might have used this approach on _new_ applications on
rebuilt tracks that didn't have cab signals at all, only wayside (such
as the Reading side).

I'm not familiar with which parts of SEPTA's lines have which signal type,
nor where rule 562 is supposedly causing problems, so I can't respond.

Post by h***@bbs.cpcn.com
What's puzzling is why would they _remove_ wayside signals?

Cost, obviously.

Post by h***@bbs.cpcn.com
The PRR style cab signal is meant as a safety backup, not as a
replacement for the operational reasons you describe.

It seems to work okay for Amtrak where they've done it, though obviously PRR
signals aren't a very good match for the model.

S

[Jishnu Mukerji]

Post by Stephen Sprunk
Also, apparently the reason this is such a big problem for SEPTA,
whereas it apparently wasn't for Amtrak, is that SEPTA also lengthened
the blocks vs. the old ABS system as part of the same project...
S

I suppose they went overboard with trying to save money by both removing
block signals and in addition lengthening blocks by eliminating some,
without thinking through the consequences. Oh well....

[Art Clemons]

Post by Jishnu Mukerji
I suppose they went overboard with trying to save money by both removing
block signals and in addition lengthening blocks by eliminating some,
without thinking through the consequences. Oh well....

It's apparently not removing the block signals, those were really redundant
anyway. An engineer is not supposed to pull a train out of the terminal if
cab signals aren't working, but rather lengthening the blocks on heavily
traveled sections of track, which leaves trains running at reduced speed
for longer periods of time than under the shorter block setup.

Incidentally cab signals or signals on the side, longer blocks will produce
this effect.

[Jishnu Mukerji]

Post by Art Clemons

Post by Jishnu Mukerji
I suppose they went overboard with trying to save money by both removing
block signals and in addition lengthening blocks by eliminating some,
without thinking through the consequences. Oh well....

It's apparently not removing the block signals, those were really redundant
anyway. An engineer is not supposed to pull a train out of the terminal if
cab signals aren't working, but rather lengthening the blocks on heavily
traveled sections of track, which leaves trains running at reduced speed
for longer periods of time than under the shorter block setup.
Incidentally cab signals or signals on the side, longer blocks will produce
this effect.

Lengthening of blocks is the big problem. But cab signal of the sort in
use adds to the problem since in the absence of cab signal driven speed
control such as it is, under NORAC rules, the engineer has the freedom
to proceed at higher speed to a point closer to the next signal and
reduce speed then and be ready to stop or whatever is needed at the next
signal. So if s/he knows that the next signal is 5 miles away s/he can
take that into account in determining when to apply brakes to bring the
train down to what speed. At least this is how the situation has been
explained to me by engineers who are NORAC certified and operate on
NORAC territory as part of their day job. I am sure John Albert will
correct me swiftly if my understanding is wrong, and naturally in that
event I will stand corrected.

If SEPTA and Amtrak had the opportunity to use a more modern cab signal
system that allows mimicking such behavior but under automatic speed
control, they would actually be able to run the railroad faster than
they can following the basic block signaling rules in effect. For
example TVM 430, LZB and ETCS with balises/beacons allow such.