London Midland's stations and HQ have received the green seal of approval from a team of external auditors.
This means that all of the 149 stations managed by London Midland, as well as the company's HQ in New Street, Birmingham, have now been assessed and judged to meet the ISO 14001 Environmental Standard.
The Standard is an internationally recognised way of making environmental improvements and ensuring compliance with environmental laws and regulations.
The assessment took into account a number of long-term initiatives such as London Midland's introduction of recycling facilities at stations such as Snow Hill, and energy savings across the network.
The auditors were also impressed with eco-driving techniques being taught to drivers on London Midland's new Siemens Desiro train simulator to reduce the amount of energy consumed by trains.
Environmental Manager Kathryn Jacques said meeting the ISO 14001 Standard was another significant step in London Midland's commitment to better environmental management.
“This is the result of a great deal of hard work and demonstrates that real progress is being made across the London Midland network,” she said.
“The auditors were very complimentary about the efforts we've made and provided a lot of positive feedback.”
London Midland's Tyseley, Soho and Worcester depots already have certification, but the company is working to extend ISO 14001 to its sidings in Bletchley, Camden and Shrewsbury by the autumn.