import pandas as pd

reader = pd.read_csv(r'statek.txt',sep='\t')
#print(reader)

select = pd.DataFrame(reader)
#print(select)

load = select['Z/W'] == 'Z'
item = select['towar'] == 'T4'

# Działa daje to co chcę
tons_max = (select['ile ton'].sum())

ship = select[load & item & tons_max]
print(ship)