My emergency train stop idea

Some of the worst train crashes occur when another train crashes into a train already involved in a mishap.
This idea would end these collisions.
Railways of the World are developing different systems.
Most rely on the driver making contact with controls and
signallers using radiophone systems to report the emergency.
With any of these, speed of answering the emergency call and the speed of other driver's reactions plays a part in the outcome. Also the driver might not be in a position to ask for help.
I was a bit late submitting this idea to Network Rail here in the United Kingdom because they are well on the way incorporating a fast emergency communication system of their own so will not be using it.
Out of the many railway ideas I have submitted this I felt was the best.
If any country wants to test and use my idea below, feel free to do so. It could save lives and could be more cost effective than other systems. Or it could be added to other systems.

In the diagram train A. jumps the rails. The driver presses the train's normal
emergency contact button, but in
addition with my idea it triggers a two to three mile radius
radio transmission.
The transmission on reaching trains B. and C. instantly activates an alarm in the driver's cab and brings in the braking system. It could even be set up to shut down the
engines, a good
addition because the
transmission A. train sends out could shut down its own engines.

If the mishap was severe and the train stopped suddenly, a switch incorporating a weight, or by the severing of a cable that runs through the train to the rear cabs emergency button would
activate the transmission. The guard may be the one who
activates this rear system. The idea brings all to a stand without a phone call. Once all trains are stopped then calls can be made in regard to the emergency and to allow trains to move once
allowed. A driver seeing an obstruction on the line could activate the transmission to stop other trains.
This idea would have two more thing in its favour. If a driver
received information about a train running out of control the driver could press the emergency button and it would bring the runaway to a stand once it was in the transmissions radius. The other option could be that a rail supervisor or rail police could carry device that would send out the same transmission.

Network Rail