train.csv is the train data sets.
test.csv is the test data sets.
sample.csv is the sample submission where the second column needs to be filled with the number of seconds from 1970-1-1 00:00:00 to the estimated timestamp. The sample.csv is associated with test.csv by the index column.
The train.csv and test.csv are from the arrival information of June, 2017. The mta_1708.csv, mta_1710.csv and mta_1712.csv can also be used as the trainset which are from August, October and December of 2017.