A recording device for a railroad vehicle, comprising: detection means for repeatedly detecting, from a vehicle air-conditioning device that performs air conditioning of a passenger compartment of the railroad vehicle, a physical quantity relating to an operation of the vehicle air-conditioning device at a predetermined sampling frequency to generate time-series data indicating detection values of the physical quantity in time series; control means for controlling the vehicle air-conditioning device by outputting control orders to the vehicle air-conditioning device based on the time-series data; abnormality detection means for detecting occurrence of an abnormality in the vehicle air-conditioning device ; a tracking memory that is volatile and has a work area to which the time-series data for a predetermined tracking period and control order data for the tracking period are writable, the control order data indicating the control orders; a record holding power accumulator to store power supplied from an overhead wire and to supply the stored power as record holding power to the tracking memory , the record holding power being used by the tracking memory to hold the time-series data for the tracking period and the control order data for the tracking period in the work area; and writing means for (i) sequentially overwriting the time-series data and the control order data to the work area of the tracking memory to sequentially update content recorded in the work area to the time-series data for a latest tracking period and the control order data for the latest tracking period and (ii) stopping overwriting of the time-series data and the control order data to the work area when the abnormality detection means detects occurrence of an abnormality in the vehicle air-conditioning device . detection means for repeatedly detecting, from a vehicle air-conditioning device that performs air conditioning of a passenger compartment of the railroad vehicle, a physical quantity relating to an operation of the vehicle air-conditioning device at a predetermined sampling frequency to generate time-series data indicating detection values of the physical quantity in time series; control means for controlling the vehicle air-conditioning device by outputting control orders to the vehicle air-conditioning device based on the time-series data; abnormality detection means for detecting occurrence of an abnormality in the vehicle air-conditioning device ; a tracking memory that is volatile and has a work area to which the time-series data for a predetermined tracking period and control order data for the tracking period are writable, the control order data indicating the control orders; a record holding power accumulator to store power supplied from an overhead wire and to supply the stored power as record holding power to the tracking memory , the record holding power being used by the tracking memory to hold the time-series data for the tracking period and the control order data for the tracking period in the work area; and writing means for (i) sequentially overwriting the time-series data and the control order data to the work area of the tracking memory to sequentially update content recorded in the work area to the time-series data for a latest tracking period and the control order data for the latest tracking period and (ii) stopping overwriting of the time-series data and the control order data to the work area when the abnormality detection means detects occurrence of an abnormality in the vehicle air-conditioning device . <EOS>