Eight thousand and nine hundred train and subway passengers were observed in the autumn of 1999. The observers included 32 trained female college students. In 1987, we observed 7,820 people and in 1997, 5,602 people. This study was performed using the same methods. The data were compared with the past two sets of data that were collected previously (1987 and 1997). Though other items were observed, this report focuses only on the activity people did while on trains and subways. Forty point nine percent of the total number of subjects observed in 1999 were engaged in some activity. In 1997, this percentage was 32.7 %, and it was 31.9 % in 1987. Reading was the most common work-related activity. However, in 1999 the most common activities involved, cellular phone, and computers, etc., other than reading which increased to 16.9% in 1987, 28.3% in 1997, and 33.1% in 1999.