I Don't Understand Railroad Communications

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KCChiefs9690

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Can someone explain it to me, or is there a link out there? I've always been interested by the railroads, but I just don't understand it like I do Public Safety, or Aviation communications...

1. What is the radio used for in a railroad enviroment? And what's the difference between a "road" channel, and a "dispatch" channel?

2. Many times I hear DTMF tones on the dispatch channel, what is it for?

If someone could explain the basics of RR communications or point me to a "beginners" link, that would be great. I just don't understand what is said on the radio and why :)
 

cquirk

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Can someone explain it to me, or is there a link out there? I've always been interested by the railroads, but I just don't understand it like I do Public Safety, or Aviation communications...

1. What is the radio used for in a railroad enviroment?
Depends on the railroad, but everything from emergency communications to the the loading and unloading of trains. I listen for dispatches to sort out where trains are, then listen for defect detectors to know when a train is passing a certian point or mile maker. There are also telephone networks via radio, then fiber optics or microwave.

And what's the difference between a "road" channel, and a "dispatch" channel?

Depends on the railroad but most are the same thing, road channel some times is used for communications between trains on the same track or area

2. Many times I hear DTMF tones on the dispatch channel, what is it for?

As stated earlier the tone activates a dispatch position or activates/opens a squelch on a train radio. They are also used to dial telephone numbers in a internal PBX system. Have also seem them used to open gates, close gates, switch tracks, acknowledge reciept of a dgital message, send weights and car numbers, send time card information etc.

Might want to go to railroadradio.net and poke around the forum. also there is a yahoo group called railscan that has more than you ever wanted to read about the subject.

If someone could explain the basics of RR communications or point me to a "beginners" link, that would be great. I just don't understand what is said on the radio and why :)[/QUOTE]
 

traffic27fl

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A couple observations on this topic. First, the railroads have agreed to switch to 6.25 digital NXDN technology. My understanding is that it is already being installed in yards and that as soon as it is certificated by the FCC for mainline use it will be installed on mainlines as well. Second, for an overview of railroad communications from beginning to future see the following white paper: http://www.tessco.com/yts/partner/manufacturer_list/vendors/sti-co/pdfs/STI-CO-Wireless-PTC-V23.pdf

The railroads are also planning to use 220mHz for a comprehensive PTC (Positive Train Control) system and this article gives an overview of this program as well.
 

KC9LQV

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1. What is the radio used for in a railroad enviroment? And what's the difference between a "road" channel, and a "dispatch" channel?

2. Many times I hear DTMF tones on the dispatch channel, what is it for?
At least around here, CSX uses the road channel/dispatcher channel setup like this:

For any particular railroad line, trains call their signals, talk to each other, and listen for defect detectors on the "road" channel. If a train needs to talk to the dispatcher, they switch to the dispatcher channel and "ring them up" with the tones you've heard. The dispatcher does not normally monitor the radio, so the tones trigger an alert on the dispatcher's console informing them that someone is calling them and where they're calling from.

If the dispatcher needs to call a train, they will usually call the train on the road channel and ask them to move to the dispatcher channel.

The main advantage of this setup is that the train and dispatcher can have a long conversation, like copying a slow order, without tying up the road channel. A few days ago, I heard the dispatcher read an entire train consist to a crew, line by line. Definitely too involved for the road channel.

HTH
 

pbryan

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At least around here, CSX uses the road channel/dispatcher channel setup like this...
In contrast, the Norfolk Southern tends to not have separate dispatcher channels, instead the dispatcher will simply use the "road" channel... A train will still generally use the calling tones to initiate contact with the dispatcher.


Depending on where you are monitoring railroad radio, you'll get different things...

If you are near a yard or terminal, there is generally lots of traffic about assembling trains, and moving trains in and out of yards...

If you are along the main line somewhere away from a yard, most transmissions will be short. Trains calling out signal indication, usually something like Train ID #, signal indication, signal location, i.e. 31V Clear 32.6 West, or 56Q Approach Belleville East. You might also hear a talking defect detector announcing a train has gone past (usually) without defects. And the occasional call to the dispatcher to get a signal changed, or some other request.

--Paul
 

FLRAILMAN

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zerg901

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I think that SELCAL is short for 'Selective Calling'. Maybe a trade name for some manufacturers paging system. Peter sz
 

ke5fnb

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I was once like you and I still am to some degree.

In my area, the "ROAD" channel is for calling the dispatcher and communicating with other trains using the line. They use base and mobile simplex and NOT repeaters where I live. There are several radio towers along the line, all tuned to the same frequency. 1212 is the channel, which means the locomotive radio transmits and receives on channel 12 (160.29 MHz.) There is a tower for each portion of a track. These towers constantly monitor the channel for a DTMF (telephone digits) tone sequence. When it hears that correct tone sequence, it activates the telephone at the dispatchers office and also repeats and audiable tone back to the engineer and conductor. Tower 1 might have the tone sequence 741; tower 2 might have 742, etc. To call the dispatcher, the conductor keys up their radio, dials the tone to the corresponding tower and is connected to the dispatcher. Sometimes the dispatcher answers immediately if he/she isn't busy. I would imagine something flashes on a computer screen at the dispatcher's console indicating which tower received the call.

He/she would connect to that aforementioned radio tower and say "Dispatcher answering tower 1"

Now, since this is a simplex system, you might only be able to hear the dispatcher (since the radio towers have better antennas and put out more power.) Sometimes you will also be able to hear the train crew (if you are close to to a passing or parked train.)

Now there are three types of traffic control, which are verbal instructions that the dispatcher gives the train and crew for which tracks to occupy.

The form I am most familiar with (and used on my local line) is Track Warrant Control. To be able to understand the conversation, you will need to know the mile posts, sidings, junction and towns along the line. Direct traffic control is similar and simpler, but not as flexible.

A track warrant instruction would sound like:

Warrant number 827 (my district number) dash xx, the individual warrant number.

x in box 2 (when box two is exxed or marked or checked, it means proceed from point a to point b.) this is probably the most common instruction on a warrant.

Look up track warrants on wikipedia Track warrant - Wikipedia, the free encyclopedia

that link will give detail on the meaning of each box number on a warrant.

the train crew will repeat that warrant back to the dispatcher and it will go into effect as soon as the dispatcher ok's it, along with the time it is oked.

If you have any additional questions, I will be happy to give you more information.
 

BigLebowski

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He/she would connect to that aforementioned radio tower and say "Dispatcher answering tower 1"

Now, since this is a simplex system, you might only be able to hear the dispatcher (since the radio towers have better antennas and put out more power.) Sometimes you will also be able to hear the train crew (if you are close to to a passing or parked train.)
To add to this, one of the major reasons for having a separate dispatcher channel is so that the dispatcher can actually hear who he is trying to talk to.

Imagine 20 trains within 100 miles of each other, each one is at a different location and each is calling out signals, talking to workers in a yard or on the ground, defect detectors are going off, etc. Only a few of the trains can actually hear each other, but the dispatcher on the tower with a base antenna can hear most of them. As a result, the more distant trains cannot hear either the dispatcher or the train he is talking with on the distant tower, and proceed to talk on the radio as usual since they don't know the distant conversation is taking place, talking over the other trains in the process.

With a separate dispatcher channel, the one dispatcher is talking to the one train that he needs to talk to with little or no interference.
 
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