.Taurus. wrote:Hi at all!
DutchRailnut wrote:90% of all locomotives in USA have alertors and other 10% or so still have a deadman pedal.
First, what is a alertor? Unfortunately i dont found something about it.
An alerter is a device that is tied into the brake, throttle, whistle, or bell to detect their operation. If in a given time period, none have been used, it will give the Engineer a visual as well as aural alarm which has to be acknowledged. Working any of the above controls, or pushing an acknowledge button on the control stand will cancel the alerter. If not, the alerter will apply the air brakes.
.Taurus. wrote:DutchRailnut wrote:Only about 10% of entire USA network is equipped with some kind of cab signalling device wich does not prevent a train from going tru a red but it can only pass a red at restricted speed 15 > 20 mph.
Is THIS a cab signalling device?
Yes, that is a form of cab signals. Correct me if I am wrong, the photo shows cab signals from Conrail, ex-PC, and exx_Pennsylvania Railroad. In that case it is a CSS type.
I cannot speak for all systems out there, however on the old CNW in Iowa, ATC, a simple form of cab signals that displays only two aspects, clear and restricting, is used. There is a signal injected into the rail that governs the cab signals. Relay shantys along the way divide the track into "blocks". When no train is on the block ahead, the relay shanty will send out a high signal (measured in Hertz) in the rail. An inductor on the lead locomotive will read that high signal, and display a clear cab signal. If a train is ahead in the next block, or, a broken rail or bond wire is detected, the relay shanty will inject a low signal into the rail. When the locomotive senses this low signal, it will cause a restricting cab signal to be displayed.
These signals are analog in nature, and about the same type of signal used in grade crossing devices. So good track grounds are important to keep crossing signals from malfunctioning.
.Taurus. wrote:How does the data transmission works?
The locomotive when it sees a restricting cab signal will also sound an audio alarm telling the engineer to reduce speed. If the engineer fails to acknowledge this or act withing 40 seconds, a penallty brake application will be applied. The automatic brake pipe must be put into supression, and train must come to a stop. Along with the change in cab signal indication, a high speed whistle will sound if the train is over 17 mph with a restricting cab signal displayed. As long as the cab signal remains restricting, an alarm will sound periodically that must be acknowledged or a penalty brake application will commence.
.Taurus. wrote:Can this devise stop the train for oneself, if it past a red signal?
Or is it a devise that only can help the crew to drive the train, by showing the signal status miles ahead?
ATC (Automatic Train Control) on the old CNW lines (now Union Pacific) were not designed for wayside signals. That is because for a large portion of the line across Iowa, there were no wayside signals. Of course now, UP has installed a great deal of CTC in that territory. So now if you get an Advanced Approach, Approach, Diverging, or Red signal, the signal system knows to give ATC a low signal into the track which activates the Restricting cab signal.
.Taurus. wrote:Is this a train securty system too?
I am not sure what a Train Security system might entail. Again, based on the CNW ATC, the system is all analog, a product of 1920's era technology.
As an aside, it is very very very rare that one would get a false clear cab signal. I only know of one case where this has happened, and all traffic on the line in that area was stopped until a reason was found for that incident. Upsetting to engineers who depend on ATC to tell them of trains ahead.