Cityrail have their ontime running stats online also. Some stats, anyway - they only show data for "peak hours" - trains arriving in the CBD between 6am and 9am, or leaving the CBD between 4pm and 6pm. The rest of the trains don't seem to matter.
Also, the data collection is, we are warned, a manual process. Wheee.
Anyway: for the month of May, only 62.2% of services were on time - where "on time" is redefined by Cityrail to be "No more than 4 minutes late". If you extend that to "No more than 10 minutes late", 87.5% were on time.
Connex' figures on their on-time running in Melbourne are also available. They managed to run 99% of scheduled services in May, and 92.9% were on time - in this case, "on time" means no more than 6 minutes late, and no more than 1 minute early. That's more arriving within 6 minutes than Cityrail can manage to have arrive within 10 minutes!
Note that cityrail doesn't care about early trains. That train just pulling out of the station two minutes early as you arrive puffing at panting at the station on your way to work in the morning? That was "on time", according to Cityrail.
Connex apologise heavily for the tardy performance - cityrail don't seem to care.
I shall go away now - but I have another rant planned for the afternoon. Prepare yourselves!