Rectangular, checkmark shaped craft in NM near Albu. in Dec. 1981

.on a christmas trip to grandparents in NM, we (mother, friend, brother, daughter of friend, myself)approached east side of Sandias near Alb. on I-40...lots of other cars driving along side...large rectangular (traincar shaped and in size)dropped down right in front of my mom's car...this craft was rectangular with an "added" storey at the left end of the craft...giving it a "checkmark" shape...it was very bright...actually looked like it had windows...blocky, like house windows, but not quite...it seemed to hover, "floating" just in front of us...we were all screaming "what is it???"  "don't get under it!!" and my mom's friend was taking pictures of it with an old camera...one with a disposable square flash bulb...only one picture turned out...The folks in other cars seemed to not notice this ...craft...this I remember...I looked out my window (back right)and folks didn't have a reaction to it...then it was gone...once in Alb. we stopped at a restaraunt and just sat...it wasn't a helicopter, airplane, weather balloon, etc...it was as I described. I have been looking since this time for someone who has seen or heard of such a craft.Also...before we saw the craft, we'd been singing (silly family songs) and recording them...then the craft came...didn't turn off the recorder, as it happened so fast...on the tape, we were screaming, as I described before, and when we described what it looked like and listened to the tape later, the description wasn't recorded.