Yes, many Indian trains use regenerative braking — but how and how well depends on the type of train, the electrical system, and infrastructure.

What is regenerative braking?

Regenerative braking is a system that slows a vehicle while converting some of its kinetic energy into electrical energy, which is stored in the battery instead of being wasted as heat.

How train use regenerative braking?

Trains use regenerative braking to recover energy that would otherwise be wasted as heat during braking. Instead of friction brakes doing all the work, the train’s traction motors act as generators and feed electricity back into the system.

1. Basic Principle

When a train moves, its motors use electrical energy to produce motion.
During regenerative braking, the process is reversed:

Motor → Generator

The rotating wheels turn the motor shafts.
The motors generate electricity instead of consuming it.
The generated electricity creates resistance in the motor, which slows the train down.

2. What Happens Inside the Traction Motor

Electric trains use traction motors (AC or DC). During regen braking:

The control system switches the motor into generator mode.
The kinetic energy of the train spins the armature/rotor.
An induced current is generated according to electromagnetic laws.
The electrical energy must be sent somewhere (grid, onboard storage, or resistors).

The resistance created by generating electricity provides the braking force.

3. Where the Recovered Energy Goes

Different railway systems handle the regenerated power in different ways:

A. Returned to the Overhead Line / Third Rail (MOST common)

The electricity produced is fed back into the traction power supply.
Other trains in the same power section can use it immediately.
This is highly efficient—energy is reused almost instantly.

Requirements:

The power grid must be able to accept reverse power flow.
(Modern AC substations and DC substations often include reversible converters.)

B. Stored Onboard the Train

If the power line cannot accept energy, some trains have:

1. Batteries

Energy stored and later used for acceleration.
Common in hybrid or “battery-electric” multiple units.

2. Supercapacitors

Extremely fast charging/discharging.
Useful for rapid braking/acceleration cycles (metro systems).

C. Dumped as Heat (Dynamic Braking / Resistor Braking)

If neither the grid nor onboard storage can accept the power:

Energy is dissipated in roof-mounted resistor banks.
Large cooling fans blow to prevent overheating.

This is not regenerative braking, but trains switch to this mode when regeneration is not possible.

4. Control Systems

Modern electric trains use sophisticated electronics:

Inverters/Converters

Manage the switch between traction and generation.
Shape the generated electricity to match grid voltage and frequency.

Braking Blending

Trains combine:

Regenerative braking (primary)
Dynamic/resistor braking (secondary)
Pneumatic (air) brakes (final, low-speed or emergency)

Blending ensures:

Smooth deceleration
Maximum energy recovery
Safety in all speed ranges

At low speeds (typically below 5–10 km/h), regen braking becomes ineffective, so air brakes finish the stop.

5. Benefits of Regenerative Braking

Energy Savings

Up to 20–35% reduction in traction energy consumption, depending on route and system.

Reduced Brake Wear

Friction brakes used less → lower maintenance cost.

Less Heat in Tunnels

Important for metros; reduces need for ventilation.

Better System Efficiency

Energy recovered from braking helps power other trains.

6. Example: Metro vs. High-Speed Train

Metro Systems

Frequent stops → very frequent regen cycles → high energy recovery.
Nearby trains absorb power almost instantly.

High-Speed Trains

High kinetic energy → huge regeneration potential.
But depending on infrastructure, grid may not always accept high power flows.
Often use mixed regenerative + dynamic braking at high speeds.

Limitations of regenerative braking in trains

Requires compatible infrastructure.
Regeneration may be blocked if:
- Line voltage too high
- No nearby trains to accept the energy (in DC systems)
- Substations are non-reversible

In these cases, the train automatically switches to resistor braking.