Commuters on Sydney's busiest rail lines are regularly unable to get home on time during the evening peak on weekdays, as new figures show the T1 Western and T8 South lines have been the worst performers over the last year for passengers.

Trains on the T1 Western – one of the most heavily patronised – and T8 South lines did not meet on-time performance targets during the evening peaks on three out of five weekdays in the 12 months to early July.

The T8 Airport and the T2 Inner West and Leppington lines also failed to meet on-time targets of 92 per cent of services running on time on almost half of weekdays over the past year.

Overcrowding is worst at Town Hall station during the evening peak. Credit:Ryan Stuart

The T4 Eastern Suburbs line, which benefits from the fact it is separated from the rest of the network, was the best performer during the evening peak from 3pm to 7pm. Trains on the line were on-time on 222 of the 256 weekdays captured by data from July 2 last year to July 5 this year.