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Wireless Signals?

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drayd48

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#1
Just in the past few months here is Statesville (Charlotte), NC, all the signals (green, yellow, red lights) up and down the Norfolk Southern line were added a new signals right next to the old ones but have not been turned on yet. There are also new antennas at each signal site and was questioning that is there going to be a new wireless signaling system or are they just adding repeaters for the trains. Thanks
 

W9BU

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#2
They are probably getting the line ready for Positive Train Control (PTC).

In a PTC system, all of the signals have to communicate with each other and with the equipment on the trains. In some parts of the country, they are using the 220-222 MHz band for this communication.
 

drayd48

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They are probably getting the line ready for Positive Train Control (PTC).

In a PTC system, all of the signals have to communicate with each other and with the equipment on the trains. In some parts of the country, they are using the 220-222 MHz band for this communication.
Ok thanks. So it will just be a form of wireless signals that will talk to each other?
 

W9BU

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#4
PTC is more about communications between the signals and the trains. If a train runs past a red signal, PTC will, in theory, stop the train.

The requirement for PTC has it's roots in an incident in 2008 when a Metrolink commuter train and a UP freight train collided near Chatsworth, California. The NTSB report concluded that the Metrolink train ran through a red signal because the Metrolink engineer was distracted by text messages he was sending while on duty.
 
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#5
If a train runs past a red signal, PTC will, in theory, stop the train.
Incorrect... PTC is designed to stop a train BEFORE it has the chance to run past a red (STOP) signal, not after it has already passed the signal. At the very least, if the PTC system has determined that the train is likely not going stop short of the signal it will apply the brakes on the train well in advance of passing the signal with the intention of the train stopping short of that signal, if the PTC system should miscalculate, that train will not get far beyond that signal. The PTC system knows the location of everything along the route through GPS as well as train length, train weight, train speed, track grade, distance to the stop (or restriction), and many other things, and it takes all this into account when making the decision on whether or not and when to apply the train brakes...
 
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Stopping before is correct, which poses some problems for trains that operate in a congested interlocking areas like commuter trains. It would require speeds to be lowered to conform with the stopping before the interlocking or signal based on the size length and weight of the consist. I suspect the new signals could just be wireless to cut down on maintenence and at the same time be connected to the PTC controller. There are many ways of getting the train info besides GPS as it doesn't cover everywhere like in tunnels. One method is now being used is an Easypass type transponder between the rails to judge speed and direction of a consist.
 
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#7
Wayside signals in PTC territory are equipped with radio antennas for the purpose of communicating with the train (controlling locomotive), the antennas are not there to cut down on maintenance or to communicate with other wayside signals and are an 'extension' of the existing signal system, to which their purpose is to transfer information between the PTC servers located at the dispatching center and the locomotive's onboard PTC computer.

The PTC system does NOT get/obtain train information regarding train length, train weight and other physical train information through GPS, it obtains that information from the PTC computer onboard the locomotive, which that information is manually entered into the computer by the locomotive engineer. Actual train location is obtained by GPS but physical train information is not.
 
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#8
I never said GPS gave or was used to determine weight length etc, I said there are other ways of transmitting location, speed ,and direction, those factors are included in the whole process of determining ( on the back end by the central processors) how far each train has to be away from one another to stop before an interlocking or signal. My notes on OUR system don't use wireless signals to talk to the train, (why would they it would mean a whole lot of extra processing to occur in the loco) as they talk to a central controller that then gives the proper info to the loco or propulsion part of the consist. There is a lot more going on in the back ground then just radio signals going back and forth. You have type of track, what speed can it handle, how tight are bends in track, and how far between interlockings/signals, the train operator may or may not have to input number of cars, gross weight and other parameters, or it may already be inputted before departure for the central controller to determine route and speed.

As far as signals being wireless, they don't have to be to work within PTC. All I said was they could also be wireless to cut maintenence AND be tied into PTC. Suppose a loco from another RR goes into this territory and they don't use your example of signals to train. Hows that going to work?

From the sounds of information being expressed here this is my main concern about PTC, there is NO standard, and with each RR doing something different it could cause problems.
 
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