This car was at Ivy City in December 1976. It was painted dark blue with a white stripe along the belt rail, WT letters with #200 below the stripe, and white diagonal end stripes below the end windows. The step edges were also white. There wasn't any lettering on the letter board.
Information given to me at that time was it had been purchased to operate a employee shuttle service between Union Station and the Ivy City engine terminal. The service may never have begun as the unions wanted a full crew on board.