• Does RTC/CTC use signals to pace trains?

  • General discussion about railroad operations, related facilities, maps, and other resources.
General discussion about railroad operations, related facilities, maps, and other resources.

Moderator: Robert Paniagua

  by CROR410
 
I was wondering if the RTC/CTC used signals to pace trains, and keep their movements rather steady versus having them get yellow and greens and end up playing 'accordian'??

Is there such a signal aspect that provides for a 'Clear Minus 5 MPH' type speed? I suspect the answer is "no" and maybe there is enough real life need for this level of speed control?
  by jg greenwood
 
CROR410 wrote:I was wondering if the RTC/CTC used signals to pace trains, and keep their movements rather steady versus having them get yellow and greens and end up playing 'accordian'??

Is there such a signal aspect that provides for a 'Clear Minus 5 MPH' type speed? I suspect the answer is "no" and maybe there is enough real life need for this level of speed control?
No "Clear, Minus 5" that I'm aware of. There's always an abundance of engineers more than willing to...."hose the canine." This practice produces the same results. :wink:

  by roadster
 
at some locations dsp. will set an appraoch med (30mph)or Approach limited speed(45mph) signal at a CP/Home signal and some automatics will also set reduced speed (same as above)due to conditions ahead. Usually in locations near a busy terminal.

  by DutchRailnut
 
Dispatchers can not set signals like approach or advance approach.
All a Dispetcher can do is at inerlockings either give you signal or keep it red, all other functions are set by track occupancy or route choosen.

  by shlustig
 
The signal system itself will handle the spacing of trains depending upon the number of aspects included in the system. In this country, most signal systems are speed signalling as opposed to route signalling. The indications tell the crew at what rate of speed to proceed as opposed to what specific route will be used.

The basic signals are "Clear" (Proceed at normal speed), "Approach" (Proceed not exceeding Medium Speed prepared to stop at next signal), and "Stop"/"Stop and Proceed". The next additional signal would be "Advance Approach" (Proceed prepared to stop at second signal; usually has a Limited Speed requirement). My home railroad also used the next additional signal of "Advance Approach Medium" (Proceed approaching second signal at Medium Speed) to further space traffic.

Additional signals typically used in advance of interlockings included the "Approach Limited", "Approach Medium", and "Approach Slow". These would be followed by the home signals of an interlocking / CP displaying "Limited Clear", "Medium Clear", "Medium Advance Approach", "Medium Approach", "Slow Clear", or "Slow Approach" which told the crew at what rate to proceed but not where they were going.

One of the problems causing confusion on some railroads today is the imposition of route information on speed signalling which seems to have started with the NORAC Rules. Unadulterated speed signalling provided a simple standard for the movement and spacing of trains.

  by UPRR engineer
 
JG and Dutch are the only ones on here telling it the way it is. The signals are set up to keep you from slamming into another train... AND THATS IT. (All though some signals do tell you your headed for a different track) Its not set up to space trains, its there to tell you to slow down, you might have to stop soon. So the answer to his question is no. Can the dispatcher hold a train at a contolled signal?....Yes.... Its just that simple, and thats it.

  by UPRR engineer
 
Hey CROR410? Was your question more like how does CTC differ from ABS only? Heres how it work buddy. With CTC a train dispatcher can run trains any way on any track (double or triple track, or one line with sidings) He can decide which way traffic can flow. So theres a crew change point will call MP1 (CP 1) with controlled signals at both ends with a bunch of crossovers. (a O.S.) So at the eastend of MP1 there are four mainline tracks, two for west bounds to park and two for east bounds trains to change out.(that does change with traffic demands) Two miles west from MP1 there is another controlled signal, MP2 (CP 2, Control Point at MP 2). Ten miles from MP1 is another O.S. (set of crossovers) at MP10 (CP 10) So this is how traffic gets "spaced", all four tracks at MP1 are full, two west bounds waiting to leave and two east bounds. The west bound hot shot UPS train on main #1 gets a high green light and they blast off, once they clear MP2 a loaded coal train on #2 track gets a low yellow, and this is what JG was talking about,"slugging" "stalling" insted of pulling right a way they sit there and wait for a better signal. The UPS train is almost at MP 10 before the coal train decides to leave town. The red over any signal tells the crew they are crossing over to a different track. (they know the speed threw the turn out) Train dispatchers dont want trains spread out most of the time. When they do decide to hold trains its because something else is going on forcing him to hold trains. Sometimes if there is no east bound traffic close the dispatcher could run the UPS train up one track and run the coal train up two track and get them both out of town quick, crossing the coal train back over to one track at MP 10. With CTC that is possible.

Now with trains trying to get into town. An east bound stopped at MP1 waiting for a clear track to pull into. (four, three, two main??) A east bound leaves and clears main four and the east bound at MP 1 gets a low yellow and pulls into the track threw the crossovers at 20 mph. (they know the turn out speed) Once they clear another east bound stopped at MP2 gets a high yellow, they do the thing JG was talking about and decide there gonna sit there and wait for a better signal. (train dispatcher can see this, its a controlled signal) Finally they get a double yellow, approach medium is what we use to call it. Its not set up to space trains, its telling the crew that they are going in at MP1 into eather main four or main three, do twenty threw the turn out. Theres no spacing about it, it telling them what to do. If the light at MP 2 went from a yellow to a flashing yellow they might have a high yellow at MP1 or maybe a low yellow or a low green. Lights can tell you were your going, a double yellow means your going into three or four main. Anything else would be two or one track, different turn out speeds on those switchs.

All that make any sense? CTC gives the train dispatcher more control, ABS works like an interstate that we drive on, west bounds on this track, east bounds on the other. The fast ones catch the slow ones, the fast one leave the slow ones in the dust. (all though trains can run the other direction with special permission) As soon as a train clears a block another train behind him gets a signal to pull into that block, unless its controlled by the dispatcher, the lights tell the crew what action is required after passing that signal, it does not space trains, it tells us what to do. Dispatchers hold trains at controlled signals, but they dont call it spacing. Theres a reason behind the delay.
  by UPRR engineer
 
CROR410 wrote:I was wondering if the RTC/CTC used signals to pace trains, and keep their movements rather steady versus having them get yellow and greens and end up playing 'accordian'??

Is there such a signal aspect that provides for a 'Clear Minus 5 MPH' type speed? I suspect the answer is "no" and maybe there is enough real life need for this level of speed control?
Ever see the navy launch fighters off a carrier on TV buddy? Im guessing they dont scatter after leaving the ship. Same thing on the railroad dude, get them in, and get them out. Most of the time they try to bunch trains of a like type together, keep them running tight and fast verses spred out.
  by CROR410
 
UPRR engineer wrote: Most of the time they try to bunch trains of a like type together, keep them running tight and fast verses spred out.
Yes I agree, and that is part of my point, althought I didn't day that. When a train comes up behind another it gets a 'yellow' which instructs it to reduce its speed substantially. Eventually it will get a 'green' and then will accelerate back to its 'Clear' speed. My thought was that maybe some of the RR's used an aspect that instructed a train to run at 'clear minus a wee bit' so that the train doesn't have to back off as hard and thus it will stay closer to the head train longer, minus as great of an accordian effect.

  by UPRR engineer
 
Are you talking about slack action with the train itself? or trains catching up to the one ahead of it? :-D If your talking about seeing a train take a yellow light and then seeing and or hearing the slack, thats bad train handling on the hogheads part. Nothing to do with the signals, or spacing is gonna change a bad hoghead. lol Is that what you where talking about buddy?
  by jg greenwood
 
CROR410 wrote:
UPRR engineer wrote: Most of the time they try to bunch trains of a like type together, keep them running tight and fast verses spred out.
Yes I agree, and that is part of my point, althought I didn't day that. When a train comes up behind another it gets a 'yellow' which instructs it to reduce its speed substantially. Eventually it will get a 'green' and then will accelerate back to its 'Clear' speed. My thought was that maybe some of the RR's used an aspect that instructed a train to run at 'clear minus a wee bit' so that the train doesn't have to back off as hard and thus it will stay closer to the head train longer, minus as great of an accordian effect.
Again, not all railroads are the same. An approach (hard yellow) on the IC requires no reduction in speed.

  by DutchRailnut
 
I don't know what IC uses for rules but Approach is based on both GCOR and NORAC and should carry same discription.

Indication = APPROACH

Proceed prepared to stop at the next
signal. Trains exceeding Medium
Speed must begin reduction to Medium
Speed as soon as the engine
passes the Approach signal.

  by jg greenwood
 
DutchRailnut wrote:I don't know what IC uses for rules but Approach is based on both GCOR and NORAC and should carry same discription.

Indication = APPROACH

Proceed prepared to stop at the next
signal. Trains exceeding Medium
Speed must begin reduction to Medium
Speed as soon as the engine
passes the Approach signal.
You're correct Mr. NUT, you don't know. Contrary to your mindset, you're NOT the authority on EVERY steel-wheel turning on EVERY railroad! The IC has their own rule book and has no speed whatsoever associated with their approach signal.
Rule 805.
Approach. Proceed prepared to stop at next signal.
Last edited by jg greenwood on Sun May 07, 2006 6:54 am, edited 1 time in total.

  by DutchRailnut
 
I never claim to know it all , and always willing to learn, specialy when wild claims are made from a renegade like yourself.
Last edited by DutchRailnut on Sun May 07, 2006 9:37 am, edited 1 time in total.

  by jg greenwood
 
DutchRailnut wrote:I never claim to know it all , and always willing to learn, specialy when wild claims are made from a renegate like yourself.
Renegate? :-D