The adhesive weight is the mass of what the locomotive is pulling. The total weight includes both the train cars and the locomotive. The mass of a train is usually measured using the following units- US tons, short tons, and metric tons. Locomotives run using three main sources of power, or a combination of the three- diesel oil, electricity, and steam. Early locomotives dating from the 1800's were mostly steam-driven and weighed 2700 kg to 5400 kg.
Modern trains are significantly more massive than their earlier counterparts.