date               station
30/10/2017 15:20    A
30/10/2017 15:45    A
31/10/2017 07:10    A
31/10/2017 07:25    B
31/10/2017 07:55    B

date             station    count
30/10/2017 16:00    A        2
31/10/2017 08:00    A        1
31/10/2017 08:00    B        2

df_start_tmp = df_trip[['Start Date', 'Start Station']]

times = pd.DatetimeIndex(df_start_tmp['Start Date'])

df_start = df_start_tmp.groupby([times.hour, df_start_tmp['Start Station']]).count()