Most trams operate using electrical power drawn from an external source, allowing them to move along fixed tracks. Here's a breakdown:
- Electrical Power Source:
- The most common method is drawing electricity from an overhead line using a pantograph, which is a spring-loaded arm that maintains contact with the wire.
- Older systems might use a trolley pole (a long, pivoting pole with a wheel or shoe at the end) or a bow collector (a curved metal frame that slides along the wire).
- Less frequently, a third rail located alongside the tracks provides power via a contact shoe.
- Power Delivery: The electrical current travels from the power source to the tram's motor(s).
- Motor(s) and Traction: The electric motor(s) convert the electrical energy into mechanical energy, which turns the wheels. The wheels grip the tracks, providing the traction needed to move the tram.
- Control Systems: Trams have control systems that allow the driver to regulate the speed and direction of the tram. These systems manage the flow of electricity to the motor(s).
- Braking Systems: Trams employ multiple braking systems, including regenerative braking (which converts kinetic energy back into electricity), friction brakes, and often, emergency brakes.
- Dual Power Systems: Some trams are equipped with dual power systems. They use electricity in urban areas but can switch to diesel power in areas without overhead lines.
- Tracks: Trams run on fixed tracks embedded in the road surface, guiding their movement and ensuring they stay on course.
In summary, trams work by drawing electrical power from an external source (typically overhead lines), using this electricity to power electric motors that turn the wheels and propel the tram along its fixed tracks.
