Why I like rail signaling so much.

[CrazyDiamond]

Yes it is interesting. GPS will prove to me like any other technology. 20 years from now, all 'significant issues' will be resolved and it will be used widely, either alone, or in conjuction with something else..... i.e. the Internet.

Interestingly enough, there is going to be a launching of a whole new slew of GPS satellites that not not owned by the USA miltary.

[chad thomas]

I think GPG will be a key element in future traffic controll but it needs to be more accurate and more RELIABLE first. Then you would have to deal with tunnels and deep canyons in a special way. GPS works by timeing when signals arrive at the unit from at least 3 satellites to triangulate from. When you don't have a good wide view of the sky it doesn't work. I have wondered about how they will handle this, especially in tunnels. And another thing, if the GPS based system has a GPS failure, what kind of backup system would they use?

[beaulieu]

CrazyDiamond the Europeans are slowly going to GSM-R for signal transmissions and radio communications in conjunction with ERTMS and ETCS. So, it is a high grade version of cell phone technology. They are in the very early days with the first installation having just gone operational near Leipzig in Germany. All previous installations have been for test purposes.

[CrazyDiamond]

Phew...I got lots of catching up to do on this site.

Advanced GPS.....I wonder if it will become a part of RR signaling someday. The future generations of GPS promise to pinpoint a receiver with an accuracy down to an inch or two. With GPS on board, and maybe the trains communicating with some sort of wireless (broadband, or satelite?) system, the whole RR signaling system could see dramatic change in the next 20 years or so....maybe sooner.

All I know is technology companies are producing some very innovative technology, and they have the capability to build in all the fail safe and levels of reliability a customer could ask for with a business case that shows a soild return of investment.

Telecommunications companies around the world are tearing out billions of dollars of equipment and replacing it with Internet Protocol (IP) based equipment, tractor-trailor companies are investing heavily in Information Technology, including satellite, GPS and broadband communications to extract more from their fleet, airlines are starting to buy into auto-pilot technology, highways/roads/briges toll administrations and (can you belive this) various sorts of drive throughs, ticket counters/kiosks, etc, are investing in RFID technology to increase efficiency.

You can't convine me the RR signaling system will not under go some new substantial changes in the near future.

[CrazyDiamond]

If I were RR "A" I would want my own signaling equipment there too...for various reasons.

[chad thomas]

The way I understand it the railroad (b) that wants to cross the existing railroad (a) is responsable for building & maintaining the tower / interlocker, or installing the signal equiptment for automatic interlockings. Although I'm sure there are many exceptions and variances. Most interlockings I know of are either in CTC territory or are automatic (first come first serve). We don't have that many towers out west anymore.

[CrazyDiamond]

QUOTE: Originally posted by tree68

The first train in line would likely be facing an absolute signal, such as one at an interlocking or possibly controlling access to the yard.

I am assuming this includes the classic "x"and "+" style crossings where track "A" and track "B" cross?

Which brings me a new question. First the scenario: Track "A" is owned by RR "A" and track "B" is owned by RR "B". Their track cross over one another at crossing "AB", and "AB" is guarded with signals. Typically wWho owns the signals at this crossing? Do they each deploy their signals? Do they each use their own signaling equipment / cabinet? ...and then the two have some amount of signaling logic communicated between each others cabinet?

[tree68]

With some exceptions, signals are set up to allow for adequate stopping distance "at speed." In the cases cited, where trains are in "stop and proceed at restricted speed" mode, I would assume that it might be possible to have several trains backed up between two signals. The first train in line would likely be facing an absolute signal, such as one at an interlocking or possibly controlling access to the yard.

[chad thomas]

They can pull up behind eachother at restricted speed. At Cajon pass it is common for westbounds to stack up one behind the other waiting to ascend the greade. Sometimes there are as many as 4-5 trains "stacked up" bumper to bumper so to speak. Here is an example at Martinez spur, this is the 3rd in a lineup of four trains:

[CrazyDiamond]

I guess if policy allows trains to stop and then proceed at restricted speed, then I guess its safe to assume that its policy not to have an empty block between two trains.

[dldance]

So this morning I took my son to the airport. For the last 15 miles of my trip, the highway parallels the SLC to Ogden UP mainline. Southbound trains were backed up, waiting to enter the SLC yards (No room at the inn?). There were 5 consecutive blocks, each with a train in it and a red block signal protecting the rear of each train -- no open blocks in between trains.

dd

[chad thomas]

QUOTE: Originally posted by CrazyDiamond

Thanks Chad,

I thought there were two reds behind a train??

G............G.............G.......<<<TRAIN<<<.......R...........R.............Y.............FY............G
##############################################################################

Or is that on other RR like UK, subways, etc? ...and not in North America?

You might be right about two reds. Also some systems like APB (a more complex ABS) all the signals between sideings will go red in front of a train to protect against 2 trains going into single track at the same time. Have you checked out this site:
http://www.lundsten.dk/us_signaling/

[CrazyDiamond]

Thanks Chad,

I thought there were two reds behind a train??

G............G.............G.......<<<TRAIN<<<.......R...........R.............Y.............FY............G
##############################################################################

Or is that on other RR like UK, subways, etc? ...and not in North America?

[chad thomas]

G................G................G...............G.......TRAIN.......R................Y................FY...............G<<<
#########################################################################
G................FY................Y...............R.........................G................G................G................G>>>

[CrazyDiamond]

QUOTE: Originally posted by chad thomas

QUOTE: Originally posted by CrazyDiamond

At the risk of getting many differing answers again I have to ask:

Train #2 is following train #1, but is slowly catching up. It has gotter the clear signals all the way so far. However it is now approaching the block that does not have a "full clear"....so what will the signal aspect be?

Depends on how many aspects the signal system can show, in areas where there is only 3 aspects (red,yellow,green) #2 would see yellow first. If the system has 5 aspects (red,flashing red,yellow,flashing yellow,green) then #2 would see flashing yellow first.

In Canada where we have the CROR, a single headed signal can display either a solid yellow, or a flashing yellow, and the two indicate different rules. ...and what about the block before it?? what is the signal aspect??

[chad thomas]

QUOTE: Originally posted by blhanel

QUOTE: Originally posted by chad thomas

Brian,
The 555 is a very versatile multivibrator that can be used for many timing or signal generating tasks. In my signal system I use it for two things. One is for the flashing signals, the 555 is timed for a little over one second in frequency with roughly a 50% duty cycle to match what the timeing of signal flashing is. The other use is in the track detection. The 555 is used to generate a high frequency signal. That signal is applied to one rail through a coupleing capacitor (That blocks track voltage). When a locomotive is in the block that high freq signal is coupled to the other rail. Attached through another coupleing capacitor is a 567 phase lock loop chip. This 567 PLL chip has a pin (lock) that when it senses the high frequency on the 2nd rail will provide a "high" logic state. This "high" logic state is what tells the rest of the signal logic that the block is occupied. I had to add small capacitors to all the wheelsets (locos and EOT equiped cars) to shunt the high freq signal between the rails. I can't remember what frequency I used but I'm sure it was around 1200hz.

OK, I gotcha now! Any idea on the R and C values?

for 555 Frequency

1.1
-----------------------
R1+(R2+R2) x C

for the 567 lock freq

1.1
-------------
R x C




For the track detector it would be something like
R1=1K ohms
R2=22K ohms
C=.047uF

That should give you 1Khz output

and on the 567
C=.047uF
R=20K in series with a 10K pot for fine tuneing. (theoreticaly it would be 23K)

[blhanel]

QUOTE: Originally posted by chad thomas

Brian,
The 555 is a very versatile multivibrator that can be used for many timing or signal generating tasks. In my signal system I use it for two things. One is for the flashing signals, the 555 is timed for a little over one second in frequency with roughly a 50% duty cycle to match what the timeing of signal flashing is. The other use is in the track detection. The 555 is used to generate a high frequency signal. That signal is applied to one rail through a coupleing capacitor (That blocks track voltage). When a locomotive is in the block that high freq signal is coupled to the other rail. Attached through another coupleing capacitor is a 567 phase lock loop chip. This 567 PLL chip has a pin (lock) that when it senses the high frequency on the 2nd rail will provide a "high" logic state. This "high" logic state is what tells the rest of the signal logic that the block is occupied. I had to add small capacitors to all the wheelsets (locos and EOT equiped cars) to shunt the high freq signal between the rails. I can't remember what frequency I used but I'm sure it was around 1200hz.

OK, I gotcha now! Any idea on the R and C values?

[chad thomas]

QUOTE: Originally posted by CrazyDiamond

At the risk of getting many differing answers again I have to ask:

Train #2 is following train #1, but is slowly catching up. It has gotter the clear signals all the way so far. However it is now approaching the block that does not have a "full clear"....so what will the signal aspect be?

Depends on how many aspects the signal system can show, in areas where there is only 3 aspects (red,yellow,green) #2 would see yellow first. If the system has 5 aspects (red,flashing red,yellow,flashing yellow,green) then #2 would see flashing yellow first.

[CrazyDiamond]

At the risk of getting many differing answers again I have to ask:

Train #2 is following train #1, but is slowly catching up. It has gotter the clear signals all the way so far. However it is now approaching the block that does not have a "full clear"....so what will the signal aspect be?

[waltersrails]

good point i like the signals but not as much as you. i like this topic its differnt. I love new topics. so thanks

http://ztrainman.tripod.com/

[chad thomas]

Brian,
The 555 is a very versatile multivibrator that can be used for many timing or signal generating tasks. In my signal system I use it for two things. One is for the flashing signals, the 555 is timed for a little over one second in frequency with roughly a 50% duty cycle to match what the timeing of signal flashing is. The other use is in the track detection. The 555 is used to generate a high frequency signal. That signal is applied to one rail through a coupleing capacitor (That blocks track voltage). When a locomotive is in the block that high freq signal is coupled to the other rail. Attached through another coupleing capacitor is a 567 phase lock loop chip. This 567 PLL chip has a pin (lock) that when it senses the high frequency on the 2nd rail will provide a "high" logic state. This "high" logic state is what tells the rest of the signal logic that the block is occupied. I had to add small capacitors to all the wheelsets (locos and EOT equiped cars) to shunt the high freq signal between the rails. I can't remember what frequency I used but I'm sure it was around 1200hz.

[blhanel]

Hmmm, OK, I went back and looked at your schematic- what the heck does the LM555/track detector trigger off of? Transients from the loco motors reaching a threshold as they cross the detector tie-in points?

[chad thomas]

My signal system couldn't care less what voltage or freq powers the trains. DC or DCC it doesn't matter.

[blhanel]

Just an aside for the folks that have been sending me schematics and info on their MRR signaling systems- it just occurred to me that these setups probably won't work with DCC systems, right? DCC uses a constant AC voltage to power the locos.

[CrazyDiamond]

QUOTE: Originally posted by Tulyar15

Those of you interested in signalling might like to look at this site:-

http://www.signalbox.org/

It deals mostly with British pattern signalling but does have links to sites concerned with signalling in other countries.

I'm not overly impressed with that site. Now this page below is an awesome resource of good signaling sites.....and it does include the Signal Box too! [:)]

http://www.railway-technical.com/sigind.html

[chad thomas]

QUOTE: Originally posted by MP173

Chad:

Maybe you misunderstood me. On each side of the track there is a brown rail like object. Are those new tracks to be installed?

Great shot...btw

ed

Ed, I really don't know what those rails are for. It would be a logical assumption that is what they are for though. Ya know they are triple tracking the pass. They are just getting to the bottom of the canyon right now. From what I hear they will be following this track (normaly used for uphill trains) with the third track. I wonder how they will handle this overpass (not seen but right over my head is hwy 138) as there is not enough room between the pillars for 2 tracks.

[MP173]

Chad:

Maybe you misunderstood me. On each side of the track there is a brown rail like object. Are those new tracks to be installed?

Great shot...btw

ed

[JoeKoh]

if you see a B&O cpl signal along the line somewhere(like Deshler) get pics while the gettings good.
stay safe
Joe

[chad thomas]

Sorry Ed, I don't know. I don't go to that spot that often.