LIRR Back and Forth all Night!!

Hello I'm new to the board and actually found it while trying to do a search on the internet. I live about 1/4 mile west of the FH station and my apartment overlooks the tracks. SO why am I writing.... well I saw something extremely interesting last night and thought maybe someone could give me some more information on what was occuring. Starting at about 9:00 PM last night two passenger cars with no diesels attached ran from the Forest Hills station on the express track down the track towards Manhattan. After it passed my location the train returned on the same track moving the other direction. It stopped at the Forest Hills station and then proceeded to reverse direction. This back and forth went on until at least 11:30 when I went to bed. Any one have an idea of what they were doing? It seemed so very odd. The cars were empty of workers (original I thought maybe they were shuttling workers around) and thoughts or ideas would be appreciated to this weird occurance.

Thanks

What kind of car? M1s? Maybe it was the alcohol train?

thanks for the information. I really appreciate it...you solved my mystery. After reading through the site my interst in trains has peaked again. Thanks! I'm actually going to start another post for some other information.

Thanks again!