Understanding the Contents of a CTC Conversation

[trainduck1198]

I have trouble understaning the contents of a conversation between dispatchers and train crews when they are using CTC. It is mainly because the only railroad within range of my scanners is the Union Pacific Livonia Subdivision and I hardly ever hear them. I don't know if this is a technical issue or what, but it would be awesome if I could hear their traffic. The BNSF Lafayette Subdivision passes through the outskirts of my town and they use TWC (which I am pretty familiar with.) For whatever reason; I am able to hear the tower transmissions from Kansas City Southern and Canadian National frequently and they both use TWC. What gets me is that they are further from me than the UP Livonia Sub. Anyway, the reason why I am posting in here is I want to better understand what exactly is being said when CTC is in use. I have searched the internet to better understand, but I found nothing. DTC is not used in my area but since it is so similar to TWC, I think I could pick it up easily. Somone, anyone, please help.

 

[Pat]

With CTC what you hear is often just bits and pieces of what is going on. If the train is routed through they may pass without any conversation. Near me the dispatcher will give a train a heads up on an upcoming meet but it's miles in advance. If the maintainers are out I sometimes get an idea what's coming. Other than that the detectors talk more than the dispatcher. Have you looked at ATCS monitor?

 

[Crow]

In CTC signals grant authority, but in TWC, the Track Warrant is what grants authority. So even if in TWC ABS a train has a green signal, if the TW is only to Milepost 123 and signal 123 is green, the train must stop at MP 123. TWC involves much more talking. in CTC, the dispatcher lines signals via a computer and if the signal is a proceed indication, the train can take it without ever talking with the dispatcher. There are rules when the train crew must call the signals, and like Pat said above, the dispatcher tends to talk to crews about meets, but there is no requirement to do so.

 

[trainduck1198]

In CTC signals grant authority, but in TWC, the Track Warrant is what grants authority. So even if in TWC ABS a train has a green signal, if the TW is only to Milepost 123 and signal 123 is green, the train must stop at MP 123. TWC involves much more talking. in CTC, the dispatcher lines signals via a computer and if the signal is a proceed indication, the train can take it without ever talking with the dispatcher. There are rules when the train crew must call the signals, and like Pat said above, the dispatcher tends to talk to crews about meets, but there is no requirement to do so.

I had tried it when I had a Windows computer but my scanner didn't pick up the 800 MHz band. Now I have two scanners that pick it up, but no computer with Windows. What about EOT monitor?

 

[trainduck1198]

In CTC signals grant authority, but in TWC, the Track Warrant is what grants authority. So even if in TWC ABS a train has a green signal, if the TW is only to Milepost 123 and signal 123 is green, the train must stop at MP 123. TWC involves much more talking. in CTC, the dispatcher lines signals via a computer and if the signal is a proceed indication, the train can take it without ever talking with the dispatcher. There are rules when the train crew must call the signals, and like Pat said above, the dispatcher tends to talk to crews about meets, but there is no requirement to do so.

Right, I am well familiar with TWC and how it works. The Lafayette Subdivision uses TWC and ABS. What would a CTC conversation sound like? I hardly ever get to hear one and when I do, it's not the whole thing since my scanner isn't up to par. It explains plenty that there is sometimes no traffic heard on the frequency for a while. What about when the crew has to call a signal?

 

[Run 8]

There just isn't much to talk about. When things are flowing, and everything is working right, there may be no communication at all. Depending on the particular RR and CTC system the signals convey authority, (ability to occupy and move on the main track) instructions (signal tells crew what to expect at the next signal, if they will continue on the main, go into a siding, cross over to another track, etc) and in some cases speed to operate. Only time there is a need to communicate, is when a train calls the dispatcher, tells him/her what they want to do, and requests signals. Occasionally a signal or switch won't work properly, and the dispatcher will call to give the crew permission to pass the stop signal, or stop and inspect or operate a power switch in hand mode. Other than that, it's just general communication-where are you in the block, do you need to stop to do switching en route, will you make it in before you expire HOS, etc. the exception, is when track work is going on, then there could be a lot of comm between the dispatcher and track gang using track and time, train coordination, form B Track Billetins etc or other means of protection.

 

[RCH]

Other than what's mentioned above, the chatter usually involves finding out where the opposing train is located when making a meet. The reason is you generally have crossings within the siding so you don't want to block traffic, especially major roads or in towns. A dispatcher might let you know you need to hold off crossings before the meet occurs since the opposing train is far away. The dispatcher might also let you know to expect more than one train or that you'll be clearing up for Amtrak or something like that, which might mean you have to cut the crossing (that sucks).

Many times this communication is just done between opposing trains since the signals are almost always set up for the meet. In this scenario, as you come up on the approach signal to the siding, you may call to the opposing train to ask where they are located. For example, "northbound to southbound at Vega, where are you running?" or "northbound train at Vega we are coming by the approach."

Also, you have certain places where the grade is significant and you might not be able to pull the hill if you stop at the signal. In this case, you might have the dispatcher or the train ahead call you when things start moving again. The train ahead might notify you that, "we're pulling on them now, just about to clear the south end," or something like that.

A similar situation is when you stop off crossings but the signal is not in view, due to a curve or some other obstruction. The dispatcher can't tell you what the signal is, but can advise you that you should have or should be getting the signal and "pull on down."

As far as calling signals is concerned, identify your train, the signal location and aspect. For example, "UP 6787 South, CP T755, Approach."