A week after Sydney's biggest public transport timetable overhaul, rail passengers are taking more journeys than they would like on older "S-set" trains without air conditioning.
Dating to the 1970s, S-sets have been put to use in greater numbers on several lines to accommodate an extra 1500 weekly services introduced as part of the timetable changes.
A leaked Sydney Trains document shows an increase in the use of S-set trains during peak periods on the South and Inner West, Bankstown and Airport and East Hills lines.
The Inner West and South lines have the most during peak periods of the day with eight S-sets operating in the morning and six in the evening.
First rolled out in 1974, the S-sets are the oldest carriages in the Sydney Trains fleet.
And as the only trains in the fleet without air-conditioning, passengers find their journeys on them uncomfortable during the height of summer.
Labor's transport spokeswoman, Jodi McKay, said the greater concentration of S-sets on certain lines represented a "double whammy for Western Sydney commuters who face longer journeys ... sitting in out-of-date and uncomfortable carriages without air conditioning".