As many summer vacations come to a close and families return to school routines, GO Transit is preparing to cut train service on multiple lines — a months-long move that has been described as “temporary.”According to a recent GO Transit service update, the Lakeshore West, Lakeshore East, Barrie and Stouffville lines will be impacted starting as early as Saturday.The update said rail service reductions are coming to “support our rail partner (Alstom) with their advancement of crew training and certification” and to “provide the capacity for future service needs,” which relates to the ongoing GO Transit infrastructure expansion program. Here is a brief summary of notable train service changes:Barrie: Three late-day, weekday train trips cancelled, bihourly afternoon and evening weekend train service (down from hourly)Lakeshore East: Weekend train service goes to 30-minute service (down from 15-minute intervals in the afternoons and evenings)Lakeshore West: Three weekday Union Station-Niagara Falls trips cancelled, weekend train service between Aldershot and Union station goes to 30-minute service (down from more frequent service intervals in the mornings and afternoons)Stouffville: Six late-day weekend trips cancelled and one new trip added, bihourly weekend train service (down from hourly)Several bus routes will also see additional trips as part of the upcoming suite of changes.Click here for a master list of GO Transit train and bus schedules.During an unrelated news conference on Tuesday, Ontario Transportation Minister Prabmeet Sarkaria was asked about the service changes.“It’s temporary, all of those changes are temporary in nature,” he said.Sarkaria said GO Transit updates and adjusts service levels at least a couple of times a year for a variety of reasons. He cited, for example, Lakeshore West trains to Niagara Falls where slow orders are adding lengthy delays and buses are being brought in to supplement rail service.“There are impacts, or very limited minor impacts on those GO routes, but it also allows us to do more enhancements to service by doing some of the infrastructure upgrades at those sites (along the Barrie and Stouffville lines) as well,” Sarkaria said.