The "third rail" that cannot be touched

The subway track system is a high-risk area where passengers are strictly prohibited from entering. Besides the high-speed running 

trains, the high voltage electricity present in between is also a fatal danger source. Some people who are not familiar with it may 

wonder, do the rails carry electricity?

As a public transportation vehicle for the city, the subway and the trains we usually take both belong to the rail transit system. The rails 

of the subway and the trains are the same - they are not electrified.

So, where does the high voltage electricity for the track system come from?

The reason is as follows: As a urban rail transit system, the power supply system of the subway is different from that of the electric 

locomotives in general railways. The power supply methods of the subway mainly include overhead contact line power supply and 

third rail power supply.

When the overhead power supply is in use (for the subway, the voltage is 1500V), it is powered through the pantograph on the train and 

the overhead contact line (the electric energy for the power unit of the electric locomotives in the railway system also comes from the 

overhead contact line). In this way, if passengers accidentally fall in, they will not be electrocuted. The other method is third rail power 

supply. The third power rail carries high voltage electricity of 750V or 1500V. When approaching without protection, it will cause people 

to be electrocuted.

What exactly does the third rail look like?

The power collection principle of the train during operation is as follows: When the train is in motion, the pantograph of the train comes

 into contact with the third rail and obtains electrical energy.

It should be noted that during the train's operation, the pantograph is also electrified and must not be touched. The danger level is 

equivalent to that of the third rail.