A local runs on weekdays out of Lawrence, LA-1, and one out of Lowell, LO-1. Numerous MBTA commuter trains to and from Boston operate in Lowell and Lawrence on a daily baisis. Daily road frieghts through the two cities are eastbounds MOPO, SEPO, westbounds WARJ, POMO. On weeknights a turn from Lowell to Lawrence and then to Boston, LOSA, operates, and returns to Lowell from Boston as SALO. Also on weeknights the gravel train from the New Hampshire Northcoast passes through Lawrence on it's way back and forth from New Hampshire(Ossipee) to Boston, DOBO/BODO.
The freights do not run on set schedules, and sometimes are cancelled or additonal ones are run. Commuter train schedules can be found at the MBTA website.
Listen to 161.16, 161.52 and 161.4 if you have a radio scanner.