Passenger Trains > Questions on METRA PTC implementation

Does anyone KNOW how PTC will be implemented on the Metra Rock Island District Beverly Sub.?
which is mostly non-signaled? Right now I believe they use time based 10" blocking between trains
with a requirement for flag protection under certain circumstances. Speed is at least 30 mph.

How will PTC be implemented on the Metra Fox Lake line? Unless something has changed in the past few
years it is single track ABS. It has a home brew method of operation. It was originally timetable / train order
territory but when the GCOR took train orders out the line was converted to kind-of-a timetable operation
with meets put out on track bulletin. Converting to TWC would have put too much of a work load on
the C&M DS and Metra did not want to pay for another DS. I assume it would be very expensive to
computerize the current system so that it could interface with PTC. Is TWC or CTC in the future so
PTC can be implemented?

It has been a long time since I rode the Metra Electric Blue Island Branch. It was single track ABS with
a siding at West Pullman. The siding had spring switches lined so the siding was like a short stretch of single
track. Again no CTC or TWC but a home brew method of operation. How will PTC be implemented there?

Englewood Wrote:
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> Does anyone KNOW how PTC will be implemented on
> the Metra Rock Island District Beverly Sub.?
> which is mostly non-signaled? Right now I believe
> they use time based 10" blocking between trains
> with a requirement for flag protection under
> certain circumstances. Speed is at least 30 mph.

Probably just put in block signals, however it could be worked with axle counters and a back end system keeping track of occupancy and automatically issuing movement authorities.

>
> How will PTC be implemented on the Metra Fox Lake
> line? Unless something has changed in the past
> few
> years it is single track ABS. It has a home brew
> method of operation. It was originally timetable
> / train order
> territory but when the GCOR took train orders out
> the line was converted to kind-of-a timetable
> operation
> with meets put out on track bulletin. Converting
> to TWC would have put too much of a work load on
> the C&M DS and Metra did not want to pay for
> another DS. I assume it would be very expensive
> to
> computerize the current system so that it could
> interface with PTC. Is TWC or CTC in the future
> so
> PTC can be implemented?

>
> It has been a long time since I rode the Metra
> Electric Blue Island Branch. It was single track
> ABS with
> a siding at West Pullman. The siding had spring
> switches lined so the siding was like a short
> stretch of single
> track. Again no CTC or TWC but a home brew method
> of operation. How will PTC be implemented there?


The snort answer in almost all of these situation is "install CTC". All the quirky low cost signaling solutions are simply being replaced by CTC because at the end of the day the cost is in the testing and you have to do pretty much the same level of testing no matter what is installed.

For the Blue Island Branch, the line is operated under APB with absolute signals at the end of each line segment. Doesn't matter if the system uses automatic logic or CTC, PTC system will grant a movement authority based on the condition of the signal. I don't know if the Fox Lake branch operates in the same method, but if movements are governed by signals alone, the PTC system should function as it does anywhere else.

There has been a massive cantilevere installed at 101st, with signal heads in both directions for both tracks, and a wayside mast at 107th (and maybe others) and new signal huts with aerials here and there. But don’t know anything beyond this physical evidence.

Posted from iPhone

lowerberth Wrote:
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> There has been a massive cantilevere installed at
> 101st, with signal heads in both directions for
> both tracks, and a wayside mast at 107th (and
> maybe others) and new signal huts with aerials
> here and there. But don’t know anything beyond
> this physical evidence.
>
> Posted from iPhone

That's pretty conclusive evidence that CTC is being installed! I know on SEPTA and other northeastern commuter lines, all the old quirky signaling got the axe. That's the lowest cost solution.

I didn't realize that the Fox Lake branch wasn't CTC and am surprised. Looks like it has 23 Metra trains each way on weekdays, plus the daily WSOR freight at night each way.

mbrotzman Wrote:
-------------------------------------------------------

> For the Blue Island Branch, the line is operated
> under APB with absolute signals at the end of each
> line segment. Doesn't matter if the system uses
> automatic logic or CTC, PTC system will grant a
> movement authority based on the condition of the
> signal. I don't know if the Fox Lake branch
> operates in the same method, but if movements are
> governed by signals alone, the PTC system should
> function as it does anywhere else.

APB (as a signal system) is not a method of train authorization. The signals are still automatic.
The signal where the branch leaves the main line is controlled but the two absolute signals at
West Pullman and the one at Blue Island are not Controlled Signals (GCOR def.)

I sincerely hope that no programmer has come up with a system that issues movement authority
based on automatic signals, especially when opposing signals are both normally clear. Movement
authority must come from some train dispatcher controlled system (TWC, CTC, DTC, etc.)

APB was designed as a safety feature in single track ABS to provide a back up in case train orders
were mis-read or incorrectly issued resulting in a lap of authority. Authority for movement came from
time table schedule or train order, now TW or DTC, etc.

The Fox Lake branch is just an expanded version of the Blue Island branch. The branch diverges from
the main line at Roundout. Roundout has the only controlled signal authorizing movement on the branch.
Except for the WC crossing, everything else is ABS - APB

inCHI Wrote:
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> I didn't realize that the Fox Lake branch wasn't
> CTC and am surprised. Looks like it has 23 Metra
> trains each way on weekdays, plus the daily WSOR
> freight at night each way.

It is the number of meets that determine how busy a line is dispatching wise.
I believe they never meet the WSOR with any Metra trains on the branch.

I will have to look at the timetable and see how many actual meets they have per day.

I believe the only siding on the Fox Lake branch is in Grayslake. That makes meets a little easier.

DevalDragon Wrote:
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> I believe the only siding on the Fox Lake branch
> is in Grayslake. That makes meets a little easier.

It makes it a lot easier. No need for the DS to figure
where a good meet might be made.

The Fox Lake sub is being converted to CTC with controlled sidings at Grayslake and the new Liberty siding just west of Libertyville station (west end of the platform to Winchester Road. The Milwaukee Road intended that line to have CTC some time ago but cancelled its plans.

The Beverly sub is getting block signals, I don't remember if CTC is part of the plan, too many other irons in the fire.

Tim

Thank you for the information.


metra6924 Wrote:
-------------------------------------------------------
> The Fox Lake sub is being converted to CTC with
> controlled sidings at Grayslake and the new
> Liberty siding just west of Libertyville station
> (west end of the platform to Winchester Road. The
> Milwaukee Road intended that line to have CTC some
> time ago but cancelled its plans.
>
> The Beverly sub is getting block signals, I don't
> remember if CTC is part of the plan, too many
> other irons in the fire.
>
> Tim

Englewood Wrote:
-------------------------------------------------------

>
> APB (as a signal system) is not a method of train
> authorization. The signals are still automatic.
> The signal where the branch leaves the main line
> is controlled but the two absolute signals at
> West Pullman and the one at Blue Island are not
> Controlled Signals (GCOR def.)
>
> I sincerely hope that no programmer has come up
> with a system that issues movement authority
> based on automatic signals, especially when
> opposing signals are both normally clear.
> Movement
> authority must come from some train dispatcher
> controlled system (TWC, CTC, DTC, etc.)
>
> APB was designed as a safety feature in single
> track ABS to provide a back up in case train
> orders
> were mis-read or incorrectly issued resulting in a
> lap of authority. Authority for movement came
> from
> time table schedule or train order, now TW or DTC,
> etc.
>
> The Fox Lake branch is just an expanded version of
> the Blue Island branch. The branch diverges from
>
> the main line at Roundout. Roundout has the only
> controlled signal authorizing movement on the
> branch.
> Except for the WC crossing, everything else is ABS
> - APB

It is not a PTC requirement to prevent stop signal violations or blown meets, just specifically defined train-to-train collisions. For example the positive stop point does not have to be at the signal, but the fouling point of the first trailing point crossover. (That's from the mouth of the PTC implementation technical lead at the Long Island Rail Road.) An APB system automatically prevents opposing movements from meeting at more than Restricted speed, therefore a PTC implementation can function like it does on a CTC line, enforcing positive stops at or near absolute signals, and Restricted speed when passing red automatics. I'm not saying that this will be the solution used on the few surviving APB segments, but it is legally permissible.

TWC-ABS (aka bi-directional ABS) does not provide the same protection as APB (tumbledown) so in that case the PTC movement authority would have to be tied into the track warrant system.

BTW I'm just making the assumption that the METRA Controlled Block System (?) segments you mentioned function automatically for the sake of the argument. I would suspect the absolute signals involved can be held by the dispatcher to set up meets. SEPTA had a similar system on it's Doylestown Branch that bit the dust in a cab signal project. The former Conrail Southern Tier Line between Binghampton and Port Jervis is longer example of an APB-like system with controlled holdout signals and spring switches. The Union Pacific River Sub is a western example and that is operated strictly under ABS rules.

mbrotzman Wrote:
-------------------------------------------------------

>
> TWC-ABS (aka bi-directional ABS) does not provide
> the same protection as APB (tumbledown) so in that
> case the PTC movement authority would have to be
> tied into the track warrant system.
>

I don't know how they do it on the Long Island but on roads west of Chicago
TWC-ABS is almost always APB. The AT&SF had a little bit of Overlap ABS and perhaps
some others have a bit of Overlap

> BTW I'm just making the assumption that the METRA
> Controlled Block System (?) segments you mentioned
> function automatically for the sake of the
> argument.

You don't have to assume.

Anyway, Metra6924 answered 2 of my questions in a post above.



Edited 1 time(s). Last edit at 02/21/18 07:46 by Englewood.

Englewood Wrote:
-------------------------------------------------------

> I don't know how they do it on the Long Island but
> on roads west of Chicago
> TWC-ABS is almost always APB. The AT&SF had a
> little bit of Overlap ABS and perhaps
> some others have a bit of Overlap
>

I was thinking of the BNSF Ottumwa Sub that, at least in 2014 had a bunch of DT ABS TWC. NS might also have a bunch of the non-APB bi-directional ABS. Either way, where signals alone can prevent head-on collisions then the PTC system only needs to take signal indication as input.

mbrotzman Wrote:
-------------------------------------------------------
> Englewood Wrote:
> --------------------------------------------------
> -----
>
> > I don't know how they do it on the Long Island
> but
> > on roads west of Chicago
> > TWC-ABS is almost always APB. The AT&SF had a
> > little bit of Overlap ABS and perhaps
> > some others have a bit of Overlap
> >
>
> I was thinking of the BNSF Ottumwa Sub that, at
> least in 2014 had a bunch of DT ABS TWC. NS might
> also have a bunch of the non-APB bi-directional
> ABS. Either way, where signals alone can prevent
> head-on collisions then the PTC system only needs
> to take signal indication as input.

If I understand you correctly PTC will not take into account a train's
authority to occupy the main track ( track warrant ). So it just watches
the signals and as long as the signals are not stop it will let the train
operate without authority?

Englewood, I checked with the PTC guys today. The Beverly Sub gets CTC while the South Chicago and Blue Island Branches will be ABS. As for meets on the Fox Lake line, the sidings are not long enough for WSOR. We looked at extending Grayslake or building a new siding but it wasn't feasible. At this time the WSOR trains run at night when there are no Metra trains. Sorry I can't help with schedules and meets. Being in MOW, I don't concern myself with schedules. For me, there is always a train coming.

Tim Pitzen
Roadway Engineer
Metra

No, in ABS territory PTC monitors both signals and track warrant authority. It won’t let you outside of your limits or by a stop signal.

Englewood Wrote:
-------------------------------------------------------
> mbrotzman Wrote:
> --------------------------------------------------
> -----
> > Englewood Wrote:
> >
> --------------------------------------------------
>
> > -----
> >
> > > I don't know how they do it on the Long
> Island
> > but
> > > on roads west of Chicago
> > > TWC-ABS is almost always APB. The AT&SF had
> a
> > > little bit of Overlap ABS and perhaps
> > > some others have a bit of Overlap
> > >
> >
> > I was thinking of the BNSF Ottumwa Sub that, at
> > least in 2014 had a bunch of DT ABS TWC. NS
> might
> > also have a bunch of the non-APB bi-directional
> > ABS. Either way, where signals alone can
> prevent
> > head-on collisions then the PTC system only
> needs
> > to take signal indication as input.
>
> If I understand you correctly PTC will not take
> into account a train's
> authority to occupy the main track ( track warrant
> ). So it just watches
> the signals and as long as the signals are not
> stop it will let the train
> operate without authority?

Posted from iPhone

Thank you once again, Metra 6924

Expect a train on any track, in any direction, at any time. Stay safe out there!

jointauthority Wrote:
-------------------------------------------------------
> No, in ABS territory PTC monitors both signals and
> track warrant authority. It won’t let you
> outside of your limits or by a stop signal.


That had been my understanding but I have been out of the loop for a few years.

Englewood Wrote:
-------------------------------------------------------
> jointauthority Wrote:
> --------------------------------------------------
> -----
> > No, in ABS territory PTC monitors both signals
> and
> > track warrant authority. It won’t let you
> > outside of your limits or by a stop signal.
>
>
> That had been my understanding but I have been out
> of the loop for a few years.

Track warrant information is entered into the Back End Server by the Dispatcher, and that is enforced by the PTC system.

Of course if the track warrant is to run through a territory where PTC has been temporarily taken out of service whatever reason, then the PTC system will not be around to enforce said authority. That is when one has truly dropped back into classic track warrant based operation. That would be an extremely exceptional condition.