Need for the bi-levels would cover a range of reasons from timing (electrification isn't going to happen across all the lines for quite some time), non-electrified network (Lakeshore West beyond Aldershot, Milton line, Kitchener-London line beyond Bramalea, Richmond Hill line, and Lakeshore East beyond Oshawa) which will grow significantly in service levels, and electric locomotives used to allow higher capacity during peak services. On Lakeshore West as an example there is unlikely to be less bi-levels because off-peak there is 30 minute service to Burlington today, and after electrification the service model shows (in addition to the electrified service every 15min or less) an hourly express to Burlington and an hourly express to Confederation (or beyond as Casablanca Road is being planned as the next step after Confederation) which is going to use as many bi-levels as the current off-peak services do.