Sydney Trains are nothing like the London Sub-surface lines. Nor are they anything like the national rail lines south of the Thames.
Suburban runs are longer than 40kms to the western termini. An 8 car set has seats for 950 passengers plus just as much standing room. Passenger loadings from the outer suburbs, from all directions, is heavy during peak hours thus the express services mentioned earlier. The timetables for them provide a clear run of about 16 miles from Redfern (the 1st station after Central) to Parramatta. With 6 tracks available for half the distance and 4 tracks nearly all of the way to Penrith the drivers can open them out.
For suburban working there is nothing in the UK that is in any way comparable.
London Underground is the closest, comparable:
Annual Passengers: London 1.34billion Sydney 322 million
System Length: London 250miles Sydney 506miles
Number of Stations: London 270 Sydney 178
The Sydney network is nothing like the London network, because it's way smaller, and that's before all the suburban train routes in London and LO are considered