SBB used a retrofitting measure of the B 20-73 coach for implementing a bundle of energy saving measures. These included CO2-based demand operation of coach ventilation, coach insulation and weight reduction of interior equipment (reduction of coach weight by 2 tons). A total of 10 individual energy efficiency measures with approx. CHF 53.000.-- additional costs were realised.
The revision of the first coach Bpm 20-70 was concluded and underwent extensive type tests in summer 1999. The modified coach can now be used another 20 years with a saving of 55 %  „comfort energy“ consumption. The cost-benefit proportion is 0.4 and is therefore very good. The modification of another 27 coaches of the same type has started. The total energy consumption (traction energy incl.) of an intercity train, consisting of modified coaches type Bpm, would be reduced by a total of 14 %. The experience gained in this project will be used for modernisation of 500 further similar coaches.