Why do trains need a third rail?
Why do trains need a third rail? Energized at 600 volts DC, the third rail provides electrical power to the power-train, and ancillaries of the subway cars.
Why do trains derail on curves?
On curved sections, the longitudinal (traction or braking) forces between vehicles have a component inward or outward respectively on the curve. In extreme situations these lateral forces may be enough to produce derailment. A special case of train handling problems is overspeed on sharp curves.
Has anyone survived the third rail?
Andy Morris survives 625-volt zap after being pushed onto live third rail in drunken brawl.
Why can birds sit on the third rail?
TIL Rats and birds don't get electrocuted by the third rail because they don't form a grounding connection. This is not some property inherent to rats and birds. This is because when they touch the third rail, they aren't touching anything else.
What happens if I touch the 3rd rail?
The third rail is probably the hardest danger to see. It looks just like an ordinary rail, but it carries 750 volts – easily enough to kill you. It's designed to send power to the train, but you are 70 per cent water and the perfect conductor for this electricity. If you touch the rail, you will “stick” to it.
Is it safe to walk on train tracks?
Railroad tracks are private property, not public trails. It's illegal and dangerous to walk on or near tracks unless you're using a designated crossing.
What is the difference between 3rd rail and 4th rail?
In 3rd rail systems, the current returns to the supply though the ordinary running rail(s). In a 4th rail system, a second insulated rail is provided, and current return is via a second set of pickup shoes through to the second insulated rail.
Is third rail better than overhead lines?
One of the significant advantages of third rail electrification is its cost-effectiveness. Compared to overhead lines, the installation and maintenance of the third rail system require fewer infrastructure modifications and are generally more affordable.
What happens if you put a rock on a train track?
Doing so can lead to severe damage to the train, derailment, or even endanger the lives of passengers and railroad workers. Why are there crushed stones alongside rail tracks? This is a good question with an interesting answer. The crushed stones are what is known as ballast.
Do trains run on AC or DC?
DC motors are used on trains is because of their high torque and good speed control. Compared to AC motors, DC motors can provide industry applications with a fine balance of strong starting torque and controllable speed for seamless yet precise performance.
Does every train have a third rail?
Third-rail supply is employed only by urban rapid-transit railroads operating on low-voltage direct current. … transmute the overhead wire or third-rail current to a supply of variable voltage and frequency suitable for feeding to three-phase alternating-current motors.
Is rail safer than car?
Compared to other popular forms of travel, such as cars, ships, buses, and planes, trains are one of the safest forms of transportation in the United States.
Why do trains not fall off the rails?
To help the wheels stay on the track their shape is usually slightly conical. This means that the inside of the wheel has a larger circumference than the outside of the wheel. (They also have a flange, or raised edge, on the inner side to prevent the train from falling off the tracks.)
Why aren t rats electrocuted by the third rail?
This is why birds do not die from landing on power lines, and subway rats do not get electrocuted even if they run across the third rail; they are not bridging the energized wire or rail to a grounded part of the structure.
Is rail safer than truck?
Truck crashes tend to be local and less dramatic than a pile of derailed train cars on fire, even if they're deadlier. In fact, federal data shows that rail has had far fewer incidents, deaths and damage when moving hazardous materials in the U.S. than trucks.