Currently, GO's operating strategy is to carry large numbers of peak commuters on very large bi-level trains, propelled by diesel locomotives. The trains do not move very quickly, and acceleration is relatively slow, but when you are competing with a crowded highway such as the 401 or the Queen Elizabeth Way, in peak hours, this does not matter much. GO has high cost recovery, with revenues more than 80% of operating costs.
An all-day service operates along the Lakeshore route, which in April 2013 was upgraded to run half-hourly.
On other routes, off-peak services are mostly provided by buses, which can actually be faster than the train services for journeys to or from downtown but do not provide service between intermediate stations (and do not provide the same level of comfort as a train).
GO's current service pattern serves peak commuters travelling into downtown quite well. However, it does not support the development of suburban activity nodes, which would require services that are faster and more reliable than the roads, with a service at least every 15 minutes, in both directions, throughout the day.