The UK’s largest rail franchise, South West Trains, has announced a £2.2 million investment in greener energy.

In a major overhaul of its regenerative braking system, South West claims that the modifications will both meet the green demands of the modern public while at the same time saving energy.

Over 200 trains that form part of the South West Trains network will be fitted-out with the new technology, meaning that commuters from the London-Waterloo base will be able to experience the eco-friendly option.

What the regenerative braking system essential does is harness the energy that is produced by braking. Currently, the large amounts of energy generated by engine braking are lost, however the new technology will allow it to return to a third rail system where nearby trains can draw on the supply produced.

The initiative, once complete, is estimated to save around 15 million kWh in electricity per annum on conservative forecasts. Such a supply would be enough to power roughly 3,500 homes for a year.

The South West Trains system covers around 607 miles of track and services some 190 million passengers every year. Once complete, the move is expected to reduce CO2 emissions by around 8,000 tonnes each year, based on the assumption that other trains will collect approximately 5 per cent of the energy from regenerative braking.

The first testing will begin on the popular Waterloo-Reading and Waterloo-Guildford routes while the entire fleet of 30 Class 458 trains are expected to have the new system fitted over the coming weeks.