By DENNIS WYATTThe BulletinA century ago electric train service started between Modesto and Stockton allowing residents a chance to board in downtown Manteca to travel to those two cities and points in between via the Tidewater Southern Railway.By 1916, there were 24 trains running a day. Eventually they declined to eight trains a day before they stopped running in 1932.Passenger train service could return to downtown Manteca by the end of 2018.That’s when Manteca commuters bound for the Bay Area may have two options to catch six different trains either at the new transit station being completed at South Main and Moffat or the existing Lathrop-Manteca on East Yosemite Avenue near the wastewater treatment plant. Ultimately, four trains may stop in downtown.That’s based on an aggressive timetable to extend Altamont Commuter Express service into Modesto.