Train traffic will increase on the rail line from Springfield through Hartford to New Haven starting Saturday, the Connecticut Department of Transportation warned. The ceremonial first trains of the new CTrail commuter train service won’t run until June 15. Rides will be free over the weekend of June 16-17, and regular service begins June 18. But starting Saturday, Amtrak’s portion of the Hartford Line service will commence, ConnDOT said in a news release. This will increase the number of daily Amtrak trains from 12 to 18. Also starting Saturday, CTrail trains will begin test runs of the full Hartford Line schedule of 16 weekday trips.