The aim of the paper is to support decision-making in the implementation of projects for the development of new locomotives, ensuring the achievement of established target parameters and the fulfilment of environmental requirements. Proposed ways to achieve this goal are the formation of an comprehensive assessment (CA) of projects and an incentive mechanism for efforts to implement the requirements. A wide range of heterogeneous indicators of the negative environmental impact of locomotives is taken into account in the formation of the assessment. The structure of the CA method makes it possible to identify the most critical factors of such impacts. CA is proposed to formulate requirements for newly designed locomotives for JSC Russian Railways.