A couple of days ago, I was listening to the local NS line on my scanner when I heard what sounded a lot like TouchTone™ tones. They occurred at the end of a call to dispatch. What were they for?
It lets the dispacher know someone is trying to get a hold of them. The DS often has several radio tower sites in there territory and can’t always monitor them all. So this tone alerts them tat someone in a towers territory is trynig to call them.
That would make sense. Thanks.
Good, that answers one of my questions that I never asked! [swg]
I have also heard these “tones” but normally only when I am using my rooftop antenna with my scanner, but not if I only use my rubber ducky antenna.
I get those when I’m in/south of the I-55 corridor coming out of Downtown to the NS tollroad, and all over the south side suburbs. I have a 36" magnetic whip in the back of my SUV, stuck to an old tie plate, so I get a little extra range.
Sometimes, it rings and rings and rings and finally a recording says: “I’m sorry, but the number you’ve dialed is unavailable as dialed. Please hang up and dial again.”
Makes me mad because it ties up the scanner for minutes at a time.
How the DTMF tones (Dual Tone Multi Frequency) are used varies by railroad. I hear CSX in my area key in several tones, which are followed by a single tone - undoubted proof to the crew calling that they keyed the tones correctly. Shortly thereafter (unless they are busy with someone else) the DS comes on and whatever business they need to transact goes on. As has been mentioned, many dispatchers handle multiple territories on multiple towers, so a simple “Hey Dispatcher” just won’t cut it.
On another hand, on some railroads, the tones open up a phone link with the dispatcher, as eolafan relates. The Adirondack works that way with MA&N. Usually we just use the phone at the station, but if time is of the essence, the engine crew will tone up the DS from the locomotive to handle business (it’s the only radio that will make the trip to the tower in question - handhelds won’t). Last time I heard that effort it took a couple of tries to get an answer.
There are two different tones that do 2 different things. The original question I assumed was in reguards to the road channel and the tone that gets the DSs attention or lets them know someone is waiting to talk to them. The DTMF tones are on the PBX channel and those tones are dialing telephone numbers just like any other phone would except this phone is linked on a simplex channel (an AAR channel) to the handheld radios in the field. These radios are able to dial into the phone system through a mountain top (usually) tranciever that is tied to a landline to the railroads PBX system or the local telephone company switch. This channel is usually the one the maintainance of way guys use while the road channel is kept clear for the trains (at least out here).
In the case of our mountain top tower (which in this case actually is), you just hit one number and the system automatically dials the DS…
Speed dial on a PBX? Sounds like you got some fancy high speed low drag equiptment Larry.[;)]
The first set of tones is the crew calling the Dispatcher. The second tone is the Dispatcher’s computer acknowledging someone is calling.
If you hear the tones at the END of a converstaion, it’s likely someone pressed the wrong buttons when changing channels.
For radio phone service (at least on CSX and CR) the radio’s transmitting and receiveing channels must be set to the phone channels. The transmitting channel is different from the recieving channel. Then you have to have the code to access the tower. The code occationally changes. Once you access the system, it sounds like your talking underwater.
Nick
Or they might be calling up a switch. We call it poor man’s CTC.
We have a couple of switch’s we can tone up and we’ll line ourselves into the siding.
I’d forgetten about that. We have some drawbridges that work the same way.
Nick
Zapp, if I understand what’s going on with the bridges correctly, does this mean you can raise and lower a drawbridge remotely? Don’t you have to be present at the bridge (or have someone present) to insure there is no river traffic going under the bridge?
Back in a previous, more affluent life I sailed boats in Connecticut. The sailboat I crewed had to wait for a drawbridge to open to leave Mystic Seaport for open water (the seaport is a museum located up a river.) Back at that time the bridge was controlled by a bridge keeper, who raised the bridge promptly at quarter after the hour, once an hour. If you weren’t ready to move when the bridge went up, that was too bad… you waited another hour.
I would hate to be sailing a boat and have a drawbridge impale itself on my stick. It would really be tacky if said bridge was operated by a train crew a few miles away…
Erik
I think there were two conversations. This was an NS local, btw. The first conversation was with one person telling them that the local had completed their previous job at Royal City much faster than had been budgeted, and wanted to be slotted in between two trains. The local was westbound towards the Opelika interlock downtown with CSX.
As they got close to the interlock, they sent out the tones and talked to the dispatcher requesting clearance across the CSX line.
They appeared to be on their own road frequency the whole time, but I was driving, and
may have missed a channel change between conversations.
Thanks for all the great information!
I’d have to believe that the rules/timetable would call for the crew to have the bridge in view before lowering it (since many bridges are now left in the up position unless needed for rail traffic). It may also work like the gate to our vehicle storage yard - you punch in the combination, the alarm starts beeping, then 5-10 seconds later, the gate actually starts to close.
Railroad safety would demand that you have a radio controlled switch in sight before moving it.
Larry & Erik,
The bridges in question are normally open. You approach the bridge prepared to stop. You stop on the bridge’s island circuit (much like a grade crossing).
After ensuring there is no water traffic (BTW water traffic is suppose to have the right of way), you punch the bridge code in, and the bridge goes down. If the tone doesn’t work (which is usually) a crew member has to walk over the box with manual controls to lower the bridge.
After you clear the circuit for the bridge, it goes back up.
Nick
Nick, Is there a time delay or does it lower immediately?
IIRC, it’s been a while since I’ve been down that way.
There is a warning bell, and the bridge drops almost immediately.
There is a delay after the train clears the circuit before the bridge goes back up.
Nick
Thanks, Nick. Now it makes sense. I guess there is some savings for the railroad in terms of not having a full time bridgekeeper, but I wonder how much time a crew loses slowing down for a bridge, stopping, lowering the bridge, getting started, and crossing the bridge?
Erik