A data communication system for a locomotive consist is provided. The locomotive consist includes a primary unit and one or more secondary units. The data communication system includes a fuel level sensor associated with the secondary units. The fuel level sensor is configured to generate a signal indicative of a fuel level in a fuel reservoir of the respective secondary unit. The data communication system also includes a data controller communicably coupled to the fuel level sensor. The data controller is configured to receive the signal indicative of the fuel level in the fuel reservoir of the one or more secondary units. The data controller is also configured to compare the fuel level with a predetermined threshold. The data controller is further configured to determine if the fuel level of any of the one or more secondary units is lesser than the predetermined threshold.