We live in Weatherford, TX, west of Ft. Worth. A train runs through our neighborhood. Usually it blasts one long toot - but Saturday night was different. About two a.m. the train went through and did a series of two toots - about 12 in total! We always sleep through the other because we are used to this. But, this woke us all up. And then about an hour later, they did it again.
possibly for rail workers, a series of two short blasts is used to warn workers near the track of an approaching train, this would be done when the workers are visible till than head end of the train passed them bye. This whistle signal is given even in an area with a quiet zone as it is a safety measure. My explanation is somewhat simplified over the actual rule but this would be my best explanation. hope it helps
Since it was around 2:00 am that you heard this it’s unlikely that anyone was working on or near the tracks at that time. A series of short horn blasts is used to warn anyone, or anything such as livestock, on or close to the tracks of an approaching train.