Why do the Russian railway tracks in this video carry a pulsed AC voltage? Is this for communications to the train?
Introduction to Russian Railway Tracks
Russian railways are known for their unique gauge, which is wider than the standard gauge used in most countries, measuring 1520 mm (or approximately 5 feet).
The Pulsed AC Voltage: Coded Track Circuits
What you're describing sounds like a coded track circuit. In American railroads and presumably in others, coded track circuits serve a dual purpose: detecting the presence of a train and communicating speed information to the train.
Think of the pulsing AC voltage as a radio signal. On the train, there is equipment tuned to pick up this "radio station." The rails themselves act as an antenna. By counting the number of pulses per minute, the train determines the permissible speed, which is displayed to the motorman and is governed by the train's Automatic Train Control (ATC) system. If the speed limit is exceeded, a penalty brake is applied.
Understanding the Russian Rail Signaling System
The voltage detected between the rails is indeed part of the Russian signaling system. While precise details about the Russian system are not available, a few ideas can be deduced from the evidence.
Insulated Blocks for Train Detection
For detecting the location of a train, the rails are often divided into insulated blocks. When a train enters a block, its wheels short-circuit the two rails, a signal that can be detected and used to control the signaling behind the train, ensuring safety for oncoming trains.
In-Cab Signaling
In the video, there's no visible line-side signaling, such as red and green lights. This suggests the use of in-cab signaling. The line-side signaling information needs to be transmitted to the cab somehow, and the block track voltage is one possible method. However, merely on/off signals are insufficient for conveying a range of information, so the voltage oscillations likely encode more complex data.
The oscillations suggest that data is encoded within it, but the exact encoding method remains unknown. One theory is that this data is similar to telegrams, carrying various signaling information.
While the exact method of encoding remains uncertain, the fact that the voltage oscillates strongly indicates that data is indeed being transmitted. This advanced signaling system ensures efficient and safe operation of the Russian rail network.
Conclusion
The pulsed AC voltage on Russian railway tracks plays a crucial role in both detecting the presence of trains and transmitting critical speed information to the train. Further research can delve into the specifics of the coding methods and improve understanding of this advanced signaling system.
Understanding the Russian railway system, particularly the technology behind it, can provide valuable insights into the efficient and safe operation of trains, which can be applied to enhance global railway infrastructure.