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B&O CPL signals for bi-directional running

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B&O CPL signals for bi-directional running

Unread postby stevej » Sun Oct 22, 2017 5:41 am

G'day,
I am curious about the Baltimore and Ohio Colour Position Light signal system. I have seen a specific photo displaying identical parallel signal indications of Approach Medium on double track. Obviously the track is capable of Bi-directional signal indication. But, the identical display of Approach Medium seems to infer the possibility of two trains subsequently approaching a turnout.

From my understanding of USRR signal rules, Medium indications are normally utilized at turnouts. Obviously, if this is the situation, then those turnouts must be diverging and not converging. I have posted a question about this display at a US rail forum, and have not received any informative response. I am hopeful that somebody in this forum might be able to assist.

I do realize that there are a number of other potential sequential indications possible within the B&O CPL system. I possess some B&O and subsequent CSX CPL signal rules information. Had both of the signals displayed either Clear or Approach, then I could understand the sequence.

The photo location is within Akron Ohio. The right hand track signal identified as 1305.1 and the left hand track signal identified as 1305.2. The distant view of the photo does not depict any subsequent signal display. I did ponder the possibility of one signal being a repeater indication. However, the track layout does not suggest the necessity of such a repeater signal.

I have scoured the NSW bi-directional signalled territory for any possible parallel indication on approach to turnouts. Only one such location may have such potential- the Down direction approach to Wollongong yard, with a Down train signalled to enter the Down Refuge, and on the UP Main a Down train signalled to enter the UP refuge. I have worked through Wollongong many times and have never witnessed this parallel signal display. Indeed, I am not certain if such is actually possible.

Yes, within the quad track region of the Sydney metrop, two trains approaching turnouts would be possible. However, this is not double track Bi-directional running. And naturally, our NSWR signalling system is Route Controlled and not Speed System based.

Steve.
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Re: B&O CPL signals for bi-directional running

Unread postby Danny252 » Sun Oct 22, 2017 4:35 pm

I'm a little confused as to what your question actually is. You mentioned in your post that the two signals indicating Approach Medium imply the following signals are displaying Medium Clear, as the following signals are both cleared for (different) diverging routes, which would be entirely valid.

As it is, your photo is showing the signals at Exchange Street (MP 130.5, New Castle Subdivision) in the direction of Timetable East. The following signals are at Bridge 16 (MP 132.7 ), where there are no crossovers. Following that are signals at Lambert (MP 134.8 ), protecting the converging junction onto the single line section to Warwick (MP 143.8 ).

As there clearly can't be a Medium aspect shown at Bridge 16, it therefore seems likely the aspect sequence is Approach Medium-Approach-Stop. Approach Medium/Approach Limited are used as substitutes for the Advance Approach aspect in a number of places (and railroads), as mention in this TrainOrders.com thread. It could also be that the sequence is Approach Limited-Approach-Stop, with your photo being taken when the flashing aspects were illuminated.
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Re: B&O CPL signals for bi-directional running

Unread postby stevej » Mon Oct 23, 2017 2:26 am

G'day Danny,
Thanks for your response.
I was hoping that somebody might know the specific region and be able to advise of the sequential signal potential.
The B&O CPL system does intrigue me, but I am still attempting to come to grips with the additional indications.
I have saved the two web pages from your links and will peruse them at home in detail.
I have also been attempting to locate the original photo that prompted my interest.
I have not managed to unearth it, but have found another photo taken at the same location but from a different angle.
Yes, I could only assume that if the subsequent indications were both medium, then turnouts must be diverging.
OR, that other approach medium CPL indications would occur.
Here in NSW (route controlled signalling) within bi-directional territory, other than Wollongong, the approach to turnouts is for converging turnouts.
Hence, adjacent signal indications cannot be the same.
Steve.
http://fredstuckmann.rrpicturearchives.net/showPicture.aspx?id=4682132
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Re: B&O CPL signals for bi-directional running

Unread postby Danny252 » Mon Oct 23, 2017 8:58 am

I note that the new photo you found is entitled "Approach Limited", so now we know the aspect!

I can think of many layouts in the US that would permit two parallel diverging indications. Two tracks becoming three, with parallel routes set 1 Track-2 Track and 2 Track-3 Track, or a diverging junction with crossover, with routes 1 Track-2 Track and 2 Track-Branch, both exist in multiple places.
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Re: B&O CPL signals for bi-directional running

Unread postby stevej » Tue Oct 24, 2017 3:57 am

G'day Danny,
I have now discovered a You Tube video clip featuring the specific signals shown in the photo https://www.youtube.com/watch?v=RQe8m7LGxWo which displays the signal cycling occurring with the right hand signal going from Clear to Stop, and the left hand signal displaying Approach Limited.

Yes, I can visualize the possibility of double tracks diverging into multiple tracks and the resulting indications in the rear. And, after reading the TrainOrders thread comments, I can understand some of the complexity betwixt the various USRR signal systems.

The need for some attempt at standardization for modern day crew through-working.

It would be interesting to find a track diagram for the specific location to discover just what track layout exists in advance of those signals. I find it much easier to understand the signal sequences possible when viewing a track diagram chart.

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Re: B&O CPL signals for bi-directional running

Unread postby stevej » Wed Oct 25, 2017 5:54 am

G'day Danny,

I have had success in finding the CSX New Castle Sub track chart. This does show the specific signals from the photo, 1305.1 and 1305.2 and surrounding signals plus track diagram. I can now achieve a better understanding of the situation where both signals display Approach Limited. One of the subsequent pair of signals 1327.1 and 1327.2 would then need to display Approach where the corresponding track Lambert signal displays Stop.

The situation at 1305.1 and 1305.2 being that CSX (B&O) CPL system does not portray Advance Approach indication. I had been initially confused by the original photo depicting the signals as displaying Approach Medium. This I now know to actually be Approach Limited. And, after reading the TrainOrders post, makes sense.

The cycling of signal 1305.1 in the You Tube video clip, I would possibly equate to the change in aspect at Lambert. The initial right hand track signal sequence possibly, Clear, Approach, Stop. This then altered by the granting of the road at Lambert and signal cycling through stop back to clear, the right had track being the through Main, and the subsequent signals then being either Clear or a speed indication if a reduced track speed exists at the trailing switch.

There does not appear to be a dwarf signal to exit Firestone yard in the West direction, only East bound. As both signals do not possess the subsidiary lamps below the main head, 1305.2 can only possibly display; Slow Clear, Slow Approach Slow, Slow Approach. I would presume for a west train to turnout into Firestone yard, signal 1305.2 would display Slow Approach, the right hand Main not having any connection to Firestone yard.

Here on approach to a converging turnout in bi-directional working, the train being stopped is held two signals behind the points. Unless, it arrives first and may proceed to the signal protecting the turnout where a timed track circuit exists. Once the time has elapsed for the stationary train, the road can then be set for the through train to proceed around.

Train Stop apparatus is fitted to signals within the Metrop region, including Bi-Di, but is only fitted to EMU and DMU trains. As I have stated earlier, the only location where bi-di parallel running trains might approach turnouts is Wollongong, though I have never witnessed this.

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