An identification tag reader reads identification tags on vehicles of a train consist. Identification tag identifiers are used to retrieve weights and lengths of the vehicles, and the weight and length information is used by an onboard train control system either to verify weight and length information already stored in the system or input the information initially, in either case for use in controlling the train such as in the calculation of braking curves. In another embodiment, an identification tag reader is paired with a sensor capable of detecting a condition on a train vehicle requiring maintenance, and the condition and an identification tag identifier are transmitted to maintenance personnel. The identification tag is preferably an AEI tag.