Multi-head signals in Cajon pass (BNSF) and Bayhore in SF,CA (Caltrain)

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Multi-head signals in Cajon pass (BNSF) and Bayhore in SF,CA (Caltrain)
Posted by T.Shimizu on Sunday, December 27, 2009 9:54 PM

Hi, all

 I am a Japanese railfan for north-american railroads. In recent, After learning signal rules, I am developing a signaling system for north-American type model railroads. That has been almost completed and I am trying to spread the system throught internet and so on for many modelrailroad fans. You can see how the system works in

http://www.youtube.com/user/tohrus08?gl=JP&hl=ja#p/u/4/p2HLrlbaZOg

How to assemble the signaling system is shown in my web site.

http://www.dokidoki.ne.jp/home2/tohrus/marklin.html

As shown in the movie, it works fine. However, I feel that the signal rule implemented in the system may be insufficient for enthusiasts for modelrailroading in USA. So, I am still learning the rule and have some questions. If you can answer, please teach me. Thanks.

 Q1: As well-known, in recent Cajon pass CA, BNSF constructed 3rd main track. In the next web page, few pictures for signals which I took there are shown. In my research, between Hill 582 and DrawbarFlat(Jct.of I15 and R138), there seems to be not any turnout track. But, at those two points, double-head signals (3-colored over 3-colored) are located on signal bridges. According to the north-American signal rule, multi-head signal such a double-head signal means whether any diverging (turnout) track is located around the signal or around the next signal, in my understanding. So, those doublehead signals must be rigourously single-head signals ??? Or, between those points, any turnout track is being planned to be located and not yet located there.

 http://wsim.cs.ehime-u.ac.jp/~shimizu/cajon-pass/signal-rule.html

Q2: In the most bottom of the above web page, you can see a picture of Bayshore station in Caltrain in SanFrancisco CA. This place may be famous for the gorgeous signal bridge. In fact, many triple-head signals are mounted on a bridge. But, beyond the signal bridge, there is no diverging track (There are just few converging tracks). Do you know how the middle and lower head of these signals works ?

T.S  Japan.

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Posted by Railway Man on Sunday, December 27, 2009 9:59 PM

Multiple head signals in North American practice are used to indicate both route and speed.  Multiple-head signals in advance of a turnout are not there for future turnouts, they are there to indicate a maximum speed at that signal and/or at the next signal.

In the case where a signal head is installed prior to a turnout being constructed, the head or heads are turned sideways and not activated, or masked.  

RWM

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Posted by T.Shimizu on Sunday, December 27, 2009 11:17 PM

Thanks for your immediate reply. For about a year, I am struggling against this topic. My understanding for signal rule may be wrong, but,,,,

According to BNSF signal rule for multi-head signal,

9.1.4 Yellow over Flashing-Green

Approach Limited Proceed prepared to pass next signal not exceeding 60 mph and to advance on diverging route

9.1.5 Yellow and Green

Advance Approach Proceed prepared to pass next signal not exceeding 50 mph and to advance on diverging route

These signal aspects seem to be used for diverging route at the next signal. In fact, what I observed in some places in US follow that such a multi-head signal is located at or a block before a diverging point. However, your saying is that these signal aspects can be used even if there is not any diverging route at the next signal ? If it is so, I want to know when those signal aspects is used (indicated) .

 T.S  

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Posted by Railway Man on Monday, December 28, 2009 12:54 AM

I have several years experience in signal engineering, but that actually makes me cautious to answer your question because it makes me aware of all the variations that exist in the real world, and the myriad possible reasons for them.  Thus, without actually having in hand the signal line maps and aspect charts for the actual locations you describe, it is a struggle for me to answer why the aspects are arranged specifically for the locations you are looking at.

First, a cautionary note:   Each U.S. railway has its own signal aspects and indications.  While they are all similar and follow the same basic rules, they are not all identical.  Thus, what you might observe for BNSF may not be applicable to UP, NS, CSX, CP, CN, or KCS, etc.  The commuter railways, if they rest upon a host Class 1 railway such as BNSF or UP, are tenants and the host railway sets the practice.   But on their own trackage, commuter railways can do what they wish so long as it meets Federal Railroad Administration rules.

There are numerous locations where there is a reason to place a dual-head signal more than one block space in advance of a diverging route.  These include:

  1.  Signals that repeat aspects.  If there is not sufficient braking distance between signals (this often happens in one direction only that has a descending grade), then signal aspects are repeated for one direction.  Thus you would place two Advance Approach signals in advance of the diverging route -- the 2nd repeats the 1st.
  2. Grade signals.  In U.S. practice on ascending grades a lunar signal is often used to modify a red intermediate signal.  When the lunar is lit, a train may proceed at restricted speed without first stopping and then proceeding.  This enables a following train to avoid stopping -- avoiding a potential stall or break-in-two upon restarting -- and come up behind a slow-moving preceeding train.
  3. Special aspects for situations that do not meet standard signal rules, but are unusually useful to improve operations and capacity.  These locations are designated in timetable special instructions or General Orders.  They are not common but they do exist.
  4. Aspects that are unusual because they are temporary during a track and signal construction project or signal cut-over.  For example, during a double-tracking project, the signal aspects for the existing single track entering the new double track may reuse existing signal locations and hardware, on a temporary basis until the next double-track segment is constructed and cut-over.

If you had a photograph of the location plus every signal location for 3 or 4 blocks on either side of the location you don't understand, and a diagram of the track arrangement, I could probably guess my way into the aspects and the reason for them.  With only a photo of one signal location, and no knowledge as to what is the track arrangement and signal arrangement on either side, and without having the line maps and aspect charts in hand, I am reduced to speculating and assuming, and that is of no use, is it.

RWM

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Posted by T.Shimizu on Monday, December 28, 2009 1:19 AM

Thanks for your polite reply.

1.  Signals that repeat aspects. ,,,,,,,,

I am remebering that similar signal operations are often observed in Japanese railroads. In Japan, train length is not so long and the distance between repeating signals is more narrow, so the repeating operation is more easily observed in real road sides. While, in US, train length is very long. So, it seems to be more complicated. Also, the steep grade in Cajon pass may have to be considered in the location of signals.  

In case of Caltrain, I will reseach more. Later, I may post, again here. Thanks. Happy holiday !!!

T.S, Japan.

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Posted by Paul_D_North_Jr on Monday, December 28, 2009 8:26 AM

 FirstSign - Welcome to the Forum, Mr. Shimizu. 

Second: Regarding the Cajon Pass photos that you posted at your "North-American sdignal rule" webpage - http://wsim.cs.ehime-u.ac.jp/~shimizu/cajon-pass/signal-rule.html - When were they taken ?  Especially, were they taken before/ during/ after the recent triple-tracking project ?

Third: Have you seen the long-running, massive - 22 pages of posts ! - and outstanding photo essay on that project here by K. P. Harrier, starting on 08-18-2007 at - http://cs.trains.com/trccs/forums/t/102777.aspx?PageIndex=1 , and most recently on 11-30-2009 at - http://cs.trains.com/trccs/forums/t/102777.aspx?PageIndex=22 ?  I don't know if any of it answers the questions that you have posed, but there are numerous photos of the signals and track rearrangements there.  In addition to the photos, perhaps K. P. will have some insight to your questions.

Fourth:  Although the signals and the line was recently improved/ rebuilt by BNSF, its heritage is former Santa Fe.  I don't know whether the current BNSF system-wide signal standards - or more to the point, those now in effect for this line - reflect the former Santa Fe practices, the pre-merger BN practices, or are a mix or hybrid of them, with variations to suit local conditions as RWM has indicated above.  But you may nevertheless find the following articles to be informative and of interest, especially the first one in the list:

Clairvoyance in Cajon
Trains, May 1976 page 22
how to interpret signals
( ATSF, "CROTEAU, DAVID D.", RAILFANNING, SIGNAL, TRN ) 
 

Cajon Pass revisited
Trains, September 1974 page 20
guide to Cajon Pass
( ATSF, CALIFORNIA, PASS, SP, "STEINHEIMER, RICHARD", UP, TRN )

Hot spots: gateway to Southern California
Trains, October 1993 page 76
Cajon Pass
( ATSF, CALIFORNIA, "CLEGG, ADAM", RAILFANNING, SP, UP, TRN )

Santa Fe sentinels
Trains, January 2003 page 52
how Santa Fe operated on block-signaled track
( ATSF, "HELLMAN, B. C.", OPERATION, SIGNAL, TRN )

Change comes to Cajon
Trains, February 2004 page 44
Part 2: SP arrives, Santa Fe relocates, our way of life ends
( ATSF, OPERATOR, REMINISCENCE, SP, "WALKER, CHARD", TRN )

Again, welcome.  Thanks for sharing your videos and webpage links.

- Paul North.

"This Fascinating Railroad Business" (title of 1943 book by Robert Selph Henry of the AAR)
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Posted by Paul_D_North_Jr on Monday, December 28, 2009 8:50 AM

T.S. -  

See also the many ATSF 'resources' that are linked at - http://www.qstation.org/atsfresource.html#top - a big Thanks !  Bow  to Andrew Falconer for posting it over on the ''Santa-Fe Super Hopper?'' thread at http://cs.trains.com/trccs/forums/t/165647.aspx , especially the following - 

The ''Information Sites'' on ATSF signalling at - http://www.qstation.org/atsfresource.html#Information 

The ''Railfanning Sites'' on Cajon at - http://www.qstation.org/atsfresource.html#Railfan 

- Paul North.

"This Fascinating Railroad Business" (title of 1943 book by Robert Selph Henry of the AAR)
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Posted by Bruce Kelly on Monday, December 28, 2009 9:59 AM
T.S., the short and simple answer to your Q1 is: yes, there are turnouts between Hill 582 and Drawbar Flats. These turnouts are in the form of crossovers between Main 1 and Main 2 at CP Walker, just west of the Interstate 15 overpass.
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Posted by timz on Monday, December 28, 2009 2:37 PM

As you probably know, Caltrain rearranged their signalling between the 7th St curve (in San Francisco) and Santa Clara a few years ago. They didn't change the signals at Army St (just south of Tunnel 2); those are still two heads each way. But all the other interlocking signals are now three heads, even though most of the interlockings don't have any slow-speed turnouts. (Most (?) of them don't have any medium-speed turnouts either.)

A train leaves San Francisco now and curves 90 degrees left at 7th Street and passes a three-head interlocking signal, then a two-head automatic just north of tunnel 2, then the two-head interlocking signal at Army St-- then signals 31/32 and 41/42 are both two-head automatics on both tracks in both directions. Next signals are three-head dwarfs at the south end of Tunnel 4, controlling the north end of the "four-track" section to Brisbane.

As I recall there are several other two-head automatic signals that don't precede an interlocking signal.

Here's the interlocking at Army St-- you can see the two No 14 x-overs and the two-head signals just north of the bridge over Army St.

http://www.bing.com/maps/?v=2&cp=q8rmjc4t0h2j&scene=13293837&lvl=1&sty=o

In your picture of the northward signal bridge at Bayshore (CP Tunnel, I guess they call it) I doubt that the lowest units of the signals ever show anything except red (except maybe for the right signal, which governs the freight spur). Maybe the middle units of the #2 and #3 signals (counting from the left) always show red too; possibly those two signals can show yellow over flashing green over red, but I'm guessing not. The #2 and #3 signals probably can show green or flashing yellow or yellow or red or flashing red on the top head, and their two lower heads are always red-- that's my guess.

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Posted by T.Shimizu on Sunday, January 3, 2010 11:01 PM

Thanks for all responses,

Cajon pass:

 Thanks for a very direct answer consistent with my undersanding signal rule, which I was expecting. When I visited there, I carefully reseached by using a rent-car and hard trecking, but I coundn't find the diverging track. Now, I rechecked some photos taken there. Then, I barely found a signal bridge around the west of I-15, which suggests the existence of a diverging track. The photo has been updated on my web page

http://wsim.cs.ehime-u.ac.jp/~shimizu/cajon-pass/signal-rule.html

Now, my question is cleared.  Thanks.

 By the way, as shown on the updated photo, I was very lucky. Because, I cound see that two double-stack trains simultaneously intersect I-15 by viewing from the mountain behind DrawbarFlats. In addition, a short time before, I could see that Christmas special train is climbing up. That is also very lucky because I didn't know the operation schedule.

 Caltrain in SF:

Thanks for some interesting comments. In usual, I use BART from Intl. airport to downtown. So, I almost didn't know any about Caltrain's signals. I added some photos on the web page linked above. As you say, Caltrain seems to make very mysterious signal operations (special rule ?).  At the departure signal bridge of Bayshore stn., I saw Red over Flashing-Green over Red, i.e. Limited Diverging Clear, nevertheless there is no diverging track (but there is converging tracks) until entering the next tunnel.

In addition, at some places, I observed Flashing-Red when interlocking signals change from Red to Yellow. That may suggest that CTC operation is temporally canceled ?  If you have any info for the Fl-Red, please teach me. Anyway, I will continue to reseach when I visit SF.

Thanks all.

T.S, Japan

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Posted by chad thomas on Monday, January 4, 2010 1:08 AM

T.Shimizu

In addition, at some places, I observed Flashing-Red when interlocking signals change from Red to Yellow. That may suggest that CTC operation is temporally canceled ?  If you have any info for the Fl-Red, please teach me. Anyway, I will continue to reseach when I visit SF.

Thanks all.

T.S, Japan

 

Flashing red is between hard red and hard yellow, permissive stop? CTC doesn't get cancelled or suspended. Controll point signals are controlled by both the dispatcher's input (lines switch(s) / clears route) and the track occupancy of the adjacent blocks beyond. Intermediate signal aspects (between controll points) is determined by track occupancy alone*.

 

* not counting slide fences, ect.

 

Shimizu, Could you explain your signal system design? I have designed a  signal system for a model too.

 

 

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Posted by jeffhergert on Monday, January 4, 2010 8:50 AM

chad thomas

T.Shimizu

In addition, at some places, I observed Flashing-Red when interlocking signals change from Red to Yellow. That may suggest that CTC operation is temporally canceled ?  If you have any info for the Fl-Red, please teach me. Anyway, I will continue to reseach when I visit SF.

Thanks all.

T.S, Japan

 

Flashing red is between hard red and hard yellow, permissive stop? CTC doesn't get cancelled or suspended. Controll point signals are controlled by both the dispatcher's input (lines switch(s) / clears route) and the track occupancy of the adjacent blocks beyond. Intermediate signal aspects (between controll points) is determined by track occupancy alone*.

 

* not counting slide fences, ect.

 


 

 

 

A flashing red indication is a restricting signal.  A train/engine may pass without stopping, proceeding at restricted speed.  It's telling the train or engine that it may continue, but the next block is still occupied by a preceding train/engine, the block has some obstruction that the train/engine may need to stop for (broken rail, open switch, etc) or that the train/engine will be leaving signalled track (going into a yard, siding or a main track not signalled for the direction of movement).

As Chad said, the Control Operator requests the signal to show a proceed indication.  The signal system determines from switch position, track occupancy that the best indication it can allow is a restricting at that time.  As conditions change, unless the route is to unsignalled track, the signal indication will get better as the train ahead clears more blocks.

Jeff     

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My signaling system for modelrailroad.
Posted by T.Shimizu on Monday, January 4, 2010 9:05 PM

Thanks for replies.

 Here, let me explain my developing signaling system for model railroad.

 Until now, I continued to develop my modelrailroad signaling system from more than 5 years ago, in my hobby. First, I learned signal rules for real Japanese railroads, discussing with real railroad company's engineers, such as JR-east. As a result, a Japanese modelrailroad signaling system was completed. At the time, I recognized this system can be applied for the other countries' railroads, which I am intesrested in. So, I went to North-American signaling system. It was hard to learn the rule because I live in Japan and visit US, only sometime. I learned through Internet and also privately commnicated with modelrailroad fans and retired engineers in US. As a result, the latest version of the signaling system rule is shown in

 http://wsim.cs.ehime-u.ac.jp/~shimizu/powderriver2008/usa-signal01.html

 How to assemble the hardware and the required open-source softwares are shown in

 http://wsim.cs.ehime-u.ac.jp/~shimizu/signal2009/signal2009-03.html

If you have Microchip's PIC-writer unit, you will be able to assemble them by yourself. If you want to see how the signaling system works, some youtube movies are available. E.g.,

http://www.youtube.com/user/tohrus08?gl=JP&hl=ja#p/u/13/vRvusGEh4i4

Probably, in order to install realistic signaling system in modelrailroad, many modelers use PC software, such as JMRI and Traincontroller with any primitive electric relay circuits or simple DCC signal decoders such as Digitrax SE8C. While, my signaling system works "stand-alone" and do necessarily not need PC. DCC command station may be used to individually operate interlocking signals because a homemade DCC decoder is mounted on each signal board. Instead of using PC, each signal board is connected with a serial communication cable and hence forms "a kind of network for signaling", as shown in the top figure of  

http://wsim.cs.ehime-u.ac.jp/~shimizu/signal2009/signal2009-05.html

 The latest signal rule which I have implemented in my system "mixedly" includes rules of BNSF, UP and so on. Hence, the rule may look very funny for enthusiasts of real railroad. So, I am trying to improve the signal rule to make more realistic. This discussion forum may be helpful for improving and polishing my signal system. Finally, I will make two versions of software specialized for BNSF and UP, respectively. On the other hands, this year, I am planning to supply low-cost PCBs to assemble the signal board in Tokyo (a shop in Akihabara town), Japan.

 

T.S

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Flashing-Red signal
Posted by T.Shimizu on Monday, January 4, 2010 11:51 PM

Sorry for this long discussion..... and thanks, again. For Flashing-Red in US, my understanding or saying may be fairly wrong, which is based on the analogy of Japanese railroad system........ Anyway,

In US, Flashing-Red is used when an "Interlocking signal" is trying to indicate "Red" but a train want to (or must) "proceed beyond the signal".

Is this correct ???

--------------------------- The following is my present understanding of Flashing-Red.

In many US railroad companies, Flashing-Red means something like "proceed at a restricted speed". E.g., in BNSF rule 9.1.13 (Restricting). However, the description is very unclear and insufficient for me to implement Flashing-Red in my signaling system.

Until recent, I didn't well know when Flashing-Red is indicated in real US roads. So, I couldn't implement Flashing-Red indication in my model signaling system. When I first knew it is when I viewed a youtube movie of great n-scale layout, http://www.youtube.com/watch?v=DEKQOh9jz9Q&feature=rec-HM-exp_stronger_rev-rn  In the movie, I first knew that Flashing-Red is used when a train enters a yard which will be out of CTC territory.

Generally, CTC is used to safely operate more than two trains from a place, i.e. a CTC operation center. E.g., trains and cars stagnating in yard are "locally" operated out of CTC territory. 

 In recent, I observed another case of Flashing-Red in real road. It was in Sanfrancisco (Oakland Amtrack station). First, a train arrives on a track in the station. At this time, every signal is normally operated. Surprising was after that. Another train enters the same track occupied by the first train. At this time, double-head entry signal to the track was indicating "Red over Flashing-Red".

 Probably, CTC operation center cannot directly permit that these two trains stay on a same track. More exactly, since Interlocking signal's Red may have more serious meanings different from Permissive signal's Red,  it should be very dangerous to proceed the interlocking signal indicating Red. In Japan, every train is equiped with ATS(Auto-train-stop) unit by which the train automatically stop at Red interlocking signal. If the train's driver want to anyway proceed, he (or station officer) cancel the ATS unit and hence the train enters the occupied track. In Japan, this is done out of normal CTC operation, using a special aux. signal and under local operations.

 I don't know what the Amtrack driver do to enter the already occupied track protected by Red interlocking signal. But, at least, it will not be normal CTC operation, I thought so.

 As I previously posted in this thread, interlocking signals in Caltrain in SF also indicate Flashing-Red in the transition from hard-Red to hard-Yellow. I don't know why Flashing-Red is indicated like a Permissive signal.

 

  T.Shimizu, Japan.

 

 

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Flashing-Red signal
Posted by T.Shimizu on Tuesday, January 5, 2010 12:32 AM

If you are modelrailroad fan and interested in the signaling system. Please watch the next movie. This movie is a little hard to understand what's going onConfused. So, play and directly skip to around the end of this movie, in which Red over Flashing-Red indication is manually operated by a remote control of Digitrax DCC command stationBig Smile.

http://www.youtube.com/watch?v=je_mHXHHW68&NR=1

T.Shimizu, Japan.

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Posted by steve14 on Tuesday, January 5, 2010 3:17 PM

I will try to answer your questions about the various mysteries of Caltrain's signal system. First let me note that I am a track guy, not a signal guy, but I do have some familiarity with Caltrain.

As Railwayman noted earlier, each railroad has their own special twists on how to apply the basic signal rules. Caltrain uses what is called "Speed Signalling" as opposed to "Route Singalling". That means that the signal indicates the speed a train must be going when it passes that point as different from telling the engineer where they are going and relying on them to know what the speed required ahead will be. This would typically be at a turnout where the train is going to diverge from the main line. Speed Signalling will indicate what speed the train must go through the turnout (in Caltrain's case at CP Tunnel in your Photo 10 this would be 50 MPH from the near track onto the next track to the left as it enters the tunnel). The Speed Signalling display would be Red over Flashing Green meaning Limited Clear. In Route Signalling, the display would be Red over Green meaning Diverging Clear at the speed listed in the timetable for that location.

Going through each of your Caltrain photos from your original post and noting that all speeds I quote are Passenger and that Freight would be lower in most cases:

Photo 10: Looking north at the South Limit of CP Tunnel. These are not "departure" signals for the station, they are the Absolute Signals for the control point. Trains can only enter a control point with proper authority (signal dispaly or verbal authority from the dispatcher). You see 5 signal heads because there is one other track on the right side of the platform which comes into the near track (Main Track 3). The next signal north of the tunnel is an intermediate (it has a number plate on the mast) and only serves to indicate the condition of the next block (from that signal to the next one to the north). Signals at a control point are controlled by the dispatcher. An Intermediate Signal is not.

What you see displayed in Photo 10 is a Clear signal for MT1, which would be for an express move through the station without stopping on the second track to the left.

Photo 11: Again, the display here is Speed Signalling so the meanings are different. Yellow over Flashing Green means Approach Limited. Proceed prepared to pass the next signal at Limited Speed (defined on Caltrain as 50 MPH). This signal is at the South Limit of CP Sierra and it is telling the engineer he must reduce speed to be at 50 MPH at the next signal, which will be the South Limit of CP Brisbane, just over a mile away at MP 7.0. At Brisbane, they will be taking the turnout to go from MT1 to MT3 to be able to make the station stop at Bayshore.

Photo 12: This is the South Limit of CP Brisbane where the indication is Limited Clear for the move through the turnout from MT1 to MT3 at 50 MPH.

Photo 13: This is the next signal (at MP 6.3) after the one in Photo 12, showing a clear block for the right hand track (MT3) from there to the next signal which is the South Limit of CP Geneva, at about MP 5.8. The middle two signals indicate Approach, which means proceed prepared to stop at the next signal and that trains exceeding Medium Speed (35 MPH on Caltrain) must begin reduction to Medium Speed as soon as passing this signal.

Photo 14: South Limit CP Geneva, displaying Approach Limited for the right hand track, MT3, and Stop for all others.

Photo 15: South Limit CP Tunnel, displaying Limited Clear for MT3, the platform track and Stop for all the others.

Photo 16: Looking south at the back side of the signals for the South Limit of CP Bart at the Milbrae station. This is a little confusing here since CP Bart only exists on the left hand two tracks. To the left is the Milbrae Controlled Siding and the middle track is MT1. The left two signals are governing movement NB through this control point. The right hand signal is an intermediate for MT2 for NB moves and is not part of the control point.

The signal in the lower left corner is for the North Limit of CP Bart and is only on  MT1.

Caltrain standardized on triple head signals at all control points when they rebuilt things in the early 2000's (seems strange to say it that way). This gives them a lot of flexibility is what information they can dispaly. The bottom signal is not always red. You can get such things at Red over Yellow over Green (sometimes called a Christmas Tree) which is Medium Approach Medium meaning proceed at Medium Speed (35 MPH) until the entire train clears all control point switches, then proceed prepared to pass the next signal at Medium Speed. Trains exceeding Medium Speed must at once reduce to Medium Speed. Have seen this as trains approach San Francisco around the 16th St crossing, MP 1.1.

There are many other combinations of signals that use all three heads too, but this is getting pretty long winded already.

You should also, if you haven't already, review the General Code of Operating Rules (GCOR) for the basics of the operating rules of most of the railroads in the country. The northeast has a different set of rules.  

Hope this helps.

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Posted by T.Shimizu on Tuesday, January 5, 2010 11:04 PM

I greatly appreciate your polite explanations. I learned many things from your post.

>Speed Signalling will indicate what speed the train must go through the turnout (in Caltrain's case....

In BNSF and UP, on which I focused until now, only when a "diverging" route is set, lower heads of multi-head signal works, including some advanced signal aspects. In contrast, in Caltrain, also when a (curved?) "converging" route is set, they works. That of Caltrain is the same as Germany railroad's signal which is also based on the "Speed Signaling".

By the way, Japanese railroads apply Route signaling but the signal does NOT indicate anything for the speed limit of diverging track, unlike BNSF and UP. So, driver of train must perfectly remember the speed limit of every diverging track along his running route. In addition, even if the number of diverging routes is many, the selected route is strictly indicated using a theater indicator, like UK railway.

 

>  all speeds I quote are Passenger and that Freight would be lower in most cases:

This is very inetresting. Depending on the speed limit of the coming train, the signal indication may be changed. If so, I want to observe freight trains run on Caltrain's track but probably it may be only midnight. If we walk around trackside midnight, it should look like a dangerous stranger ?Dead  Anyway, I may implement the rule on my modelrailroad signaling system.

 

 Thanks again.

P.S,  

Now, I still have a question for Flashing-Red in Caltrain, as I posted three posts above. Please teach me, if there is anyone who know what condition activates Flashing-Red when hard-Red is changed to hard-Yellow at interlocking signals  (at CP?). Probably, intermediate signals do NOT indicate it.

 

T.Shimizu, Japan.

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Posted by timz on Tuesday, January 5, 2010 11:22 PM

T.Shimizu
in Caltrain, also when a (curved?) "converging" route is set, they [lower heads] works.

Also: some automatic signals can show yellow over flashing green even though the next signal beyond is another automatic.

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Posted by steve14 on Wednesday, January 6, 2010 10:14 AM

For simplicity I only mentioned Passenger train speeds. Freights have different speeds and use the same signal with the same meaning. The difference is the definintion of the speed for each mode.

Limited Speed = 50 MPH Passenger and 40 MPH freight

Medium Speed = 35 Passenger and 25 Freight

Slow Speed = 20 Passenger and 15 Freight 

Flashing Red on Caltrain has the same meaning as on most other properties: Restricting, proceed at Restricted Speed. From the GCOR, this is defined as:

"When required to move at restricted speed, movement must be made at a speed that allows stopping within half the range of vision short of Train, Engine, Railroad Car, Men or equipment fouling the track, Stop Signal or derail or switch lined improperly. When a train or engine is required to move at restricted speed, the crew must keep a lookout for broken rail and not exceed 20 MPH. Comply with these requirements until the leading wheels reach a point where movement at restricted speed is no longer required."

A Yellow Signal indicates Approach, which means be prepared to stop at the next signal. It does not convey any set speed requirement. Restricting sets a maximum of 20 MPH along with the ability to stop within half the range of vision and to look out for any obstacles. This puts more of a burden on the engineer to be in control of the train.

As to what would activate a Restricting signal, it would depend on how the aspect string is designed within the signal system. The signals will clear up from most restrictive to least restrictive, which would mean that a Restricting aspect would be the first to appear after a Stop signal, then Approach and so on to Clear.

Some of the more signal literate members on the board can probably give a more detailed answer.

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Posted by T.Shimizu on Wednesday, January 6, 2010 9:11 PM

Thanks, again. It should be hard for you to discuss with me.

I have learned the text in GCOR but my understanding seems to be insufficient. I will learn it again. Anyway, if I were a driver, I dislike to encounter Flashing-Red which is too fuzzy to operate the train. Big Smile

By the way, now, in order to improve my modelrailroad signaling system, what I want to know can be summarized as follows.

 >A Yellow Signal indicates Approach, which means be prepared to stop at the next signal.

Until now, I have not deeply considered about this. But, this implies that a train driver encountering "(single-)hard-Yellow" must prepare to stop at the next signal "but, if the next is Flashing-Red, he can slowly proceed without stop" beyond the Flashing-Red.

Please imagine that a train is approaching another train going ahead.  How is the signal sequence which the train driver will see ?????  E,g, I imagine the next two cases.

Train1  ==>> hard-Green, Flashing-Yellow, hard-Yellow, "Flashing-Red", and then, hard-Red. ==>> Another train going ahead.

or 

Train2  ==>> hard-Green, Flashing-Yellow, hard-Yellow, and then, hard-Red.==> Another train going ahead. But, in this case, the hard-Red signal may be temporally changed to "Flashing-Red" because of "any reason", (if the signal is a interlocking signal located at a Control Point).

 

Case of Train1 is very easy pattern to understand. But probably, case of Train2 may be applied in Caltrain, I think so.  In other words, in case of Train1, when a hard-Red signal is changed to Flashing-Red is when the next signal becomes hard-Red. On the other hand, in case of Train2, "any reason" can temporally change hard-Red to Flashing-Red.

Q1: If Train2 is applied, what is the "any reason" ?

Q2:  In any cases, probably, if it is intermediate signal, since the train driver can proceed beyond hard-Red, Flashing-Red is not indicated in this case ?

 

Anyone can comment about this ?   Best regards.

T.Shimizu, Japan.

 

T.Shimizu, Japan.

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Posted by steve14 on Thursday, January 7, 2010 9:33 AM

You're getting pretty deep into signal wiring, which may be more than you need to worry about for a model layout.

The signals will change because the train ahead is moving. This means that the displays of signals behind it will continue to become more favorable for a following train so long as the first train is moving faster than the second train, putting more distance between them.

Depending on how the signal system is designed will determine exactly how the cascade of dispalys behind a train change. Remember, each railroad may do things just a little different so to say that a particular sequence will always happen is hard to do.

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Posted by T.Shimizu on Thursday, January 7, 2010 9:09 PM

In my signaling system, as a possibility, the interlocking system at CP point can work, if modeller wants and he has a skill to complete the logic. Otherwise, instead of the rigorous interlocking system, some easy setups similar to it are also possible. Anyway, to do so, additional handmade logic control units are needed, or PC software such as Traincontroller is needed. In addition, even if modeler cannot do it, my signaling system can "automatically" show behaviors similar to real things in his view, I hope so. That is my policy for the development of the signaling system. I will not implement the signaling system specialized for Caltrain, itself, but as a variation of Flashing-Red operations, it is very important for me to understand when and where Flashing-Red is activated.

Through discussions on this thread, I got many things. Now, I am planing to implememt some operations for Flashing-Red indication and also the signal aspect for converging route, as options in my signaling system.

Thanks again.

P.S

I have another question for signal indications of Multi-head signal (for variations of Diverging Approach Diverging in UP and BNSF). After some arrangements for my question, I will create a new thread for it, later.

T.Shimizu, Japan.

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Posted by timz on Thursday, January 7, 2010 9:16 PM

I can't promise this is right, but I'm pretty sure Caltrain automatic signals never show flashing red. If a train passes an interlocking signal and the dispatcher clears it immediately it will show flashing red until the train passes the next signal. If a northward train is waiting at Bayshore on track 3 and the northward express passes it on track 1, the train on track 3 might see red over flashing red over red.

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Posted by T.Shimizu on Thursday, January 7, 2010 9:39 PM

>If a train passes an interlocking signal and the dispatcher clears it immediately it will show flashing red

This is what I wanted to know. Probably, when interlocking between turnout tracks and the signal for the train going ahead is released, dispatcher will automatically do it (Red ==>> Fl-Red). So, at the time, the train will still stay on the block loosely protected by Flashing-Red signal, maybe.

 I will continue to reseach Caltrain's signal operations.

  >the train on track 3 might see red over flashing red over red.

I can understand this. This is an interesting variation of Fl-Red. Thanks.

T.S, Japan.

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Posted by Jovet on Sunday, January 10, 2010 8:18 AM

I ran across this thread during a websearch, and since I have a good practical and fundamental grasp of railroad signaling, I thought I might try and chip in.

T.Shimizu:

Your model railroad signal system looks pretty interesting.  I will study how it works more soon enough.

It can be difficult to find signaling information for railroads on the internet.  I have slowly been building my own collection of signal aspect charts.  You can refer to this page to see them.  I don't know if you've seen a general list of signal aspects for CalTrain, but that may help you understand how the system works.

North American signaling is intimidating to many people, especially foreigners.  But there is a non-obvious logic to it, and things really make sense once you grasp a few basics.  By far the best write up I've ever seen on the subject comes from an engineer for BNSF.  You can read it here.

The later part of this thread has delved into flashing red.  It's been pointed out that means Restricting but it seems you're still a bit confused what that means.  Mr. Krug touches on it, but I'll elaborate:  A Restricting aspect means the train can proceed at Restricted Speed.   Restricted speed is not a fixed speed but instead means the driver is on his own.  In Europe, it'd be called driving on sight...similar to a shunting aspect.  A train operating at Restricted speed cannot be moving faster than it is able to stop in half the distance the driver can see down the track.  There is also a maximum speed, usually 15 MPH or 20 MPH, depending on the railroad.  This ensures that the train can be stopped for whatever reason may arise.

Restricting aspects can be shown a few ways.  A lunar white or flashing red, alone or with other steady reds, always means Restricting.  Some railroads do not use either of those, and so Restricting becomes a yellow under one or two red lights.  Also, many railroads have provisions for passing permissive signals without stopping in some situations.... such as on the  BNSF with the "G" grade signs.  That aspect is also usually called Restricting.

How Restricting aspects appear is pretty straightforward.  At an interlocking, the passage of a train through the interlocking is handled by the control operator, or dispatcher.  If a train is routed into a track that does not have occupancy detection, then a Restricting aspect will result.  Since the occupancy of the track is unknown to the signal system, it would be inappropriate to show a green or a yellow.  Depending on the rules and specific track, the requirement to proceed at Restricted speed may end when the train clears the interlocking. 

Additionally, some signals are equipped to display a Restricting aspect on the specific request of the control operator.  This is called a "call-on" (ala Britain) and exists to allow the dispatcher to grant permission for a train to continue into an occupied track without stopping or having to ask.  Controlled signals or permissive signals can be equipped to do this, but only where it's useful to do so.  Some signals, particularly on Position-Light signals, display Stop and Proceed instead of Restricting during a call-on cycle.

So, in summary, CalTrain uses flashing red to indicate a Restricting aspect.  It can mean the train is routed into unsignaled territory, or the dispatcher simply doesn't want the train to have to stop. 

The third head (or arm) on the CalTrain signals can be used for providing additional speed information for the next signal.  Effective speed signaling must convey the speed limit at this signal, and a warning of the speed limit at the next signal.  Canada's C.R.O.R. signal system is a very complete signal system, and may make a good additional reference for you.  (You can see it on my page linked above.)

Hope that helps!

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Posted by T.Shimizu on Monday, January 11, 2010 8:25 PM

Thanks, Mr.Jovet,

I tried to find but have not seen the Caltrain's signal rule. That is needed to study how Caltrain operates signals. Thanks.

Before I posted on this thread, I privately communicated with Mr. Krug for North-American signaling system. His web site was very helpful to study. He kindly taught me for the basic concept hidden in the real signal rules. In fact, the latest version of my signaling system shown in my youtube movies is largely influenced by his comments and web site.

>CalTrain uses flashing red to indicate a Restricting aspect.  It can mean the train is routed into unsignaled territory, or the dispatcher simply doesn't want the train to have to stop. 

I can understand this. Probably, what I observed on Caltrain will be the latter case. Because, in usual, main (busy?) tracks are almost completely covered with occupancy detection, I think so. Sometimes, I am observing the location of the track circuit gaps for train occupancy detection around real signal mast. If I have a chance, I will observe the relation of Flashing-Red and train detection (but it may be very hard....). Thanks.


>Canada's C.R.O.R. signal system is a very complete signal system,

I also think so. Already, I have studied the signal rule through Internet, in which some complicated signal aspects like "Diverging approach diverging for Slow, Medium, and Limited" are explained. But, it is still insufficient for me to complete my signaling system. E.g., I want to know some additional combination variations of "Approach" and "Diverging" possible in real operations of UP and BNSF. In a few days, I will creat a new thread for Multi-head signal for the topic. Now, I am preparing to make my questions to be easily understandable.


T.S

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Posted by Jovet on Monday, January 11, 2010 9:50 PM

My web page with links to various signal rules is here (click on this text).  The CalTrain rules are the third link on that page.  You may find the other rules interesting for contrast.   Those rules and aspect tables are pretty general...there are surely some special aspects used in isolated situations that are not listed.  (I know for a fact, actually.) The rules listed should be pretty accurate, but no guarantees. :)

It's hard to say about the Restricting aspects. From the pictures of the CTX line I've seen, I haven't seen too many service tracks at interlockings.  But I do not live in the area, so....

A track that has occupancy detection is said to be bonded.  A track without detection is said to be unbonded.  This term comes from the act of bonding wires to the rails to create a track circuit.

It is indeed usually pretty easy to spot the insulating joint bars that break up the track circuits.  They're usually painted a bright color (often yellow) so they're easy to spot.  You will not be able to spot an unbonded siding from the track at the signal leading into the siding.  This is because the area of the interlocking itself (called the "OS tracks" or "OS area," for "on sheet" in the days of tracking train movements on paper) is bonded.  Part of the point of interlocking of the signals is that a train cannot be in the interlocking if a route is to be lined through it and a signal is to be cleared...so all the tracks in the interlocking will have occupancy detection (as much as possible).  To spot an unbonded siding you'd have to trespass on railroad property and actually examine the insulated joints of the siding in question to see if it has wire bonds on just the interlocking side of the joints or wires on both sides.  Trespassing is a bad idea, so just careful observation of the signals over time can let you figure it out on your own.

"Diverging Approach Diverging for Slow, Medium, and Limited" is a contradiction.  Remember that the only real difference between Route signaling and Speed signaling is that Speed signaling, each "diverging" movement has a signal aspect that gives a specific speed limit.  In route signaling, the signal aspect implies a route to be taken, and that route has a speed limit that the engineer must already know.  Different route aspects can be shown in Route signaling, implying diffrerent speed limits, but the speed limits all come from the Timetable, not the signal aspect itself.   Diverging Approach Diverging is a Route signaling aspect.  Route signaling won't really care about Slow or Medium or Limited speed at the next signal.  Speed signaling would...and it would have Medium Approach Medium or Limited to Slow or whatever is fitting instead. 

When you see a Diverging Clear or a "Diverging _______" aspect, that is a Route signaling system.  When you see a "Medium _______" or "Limited ________" or "Slow ________"  that is usually a Speed signaling system.   BNSF has an Approach Medium aspect.  The aspect name doesn't start with "Medium" so it will not imply a Speed signaling system.  (Instead it's just a "control your train!" aspect.)   Medium speed may have an informal definition on the BNSF system, but that definition is not used for diverging routes via signal aspects.

My signal rules sheets for BNSF and UP (should) show all the "Diverging _____" aspects you'll want to learn about.

If you have any desire to contact me directly by email, you surely can.  There is a link to send me an email on my profile on here.  We might not want to put all these people to sleep. Wink

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Posted by blue streak 1 on Monday, January 11, 2010 11:03 PM

Jovet

Your site with these signals is great help for those of us who are out in the field. Keep us posted whenever you update any RR. Thanks very much.

 

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