I occasionally have to fly to the DC area for work conferences. I have one such coming up next month in College Park, MD. In the past I've always flown into National (wonderfully easy access to the Metro) or Dulles (just hopeless, not much choice but uber or taxi at least part way into town.) This time I've been sent to BWI. Now, on paper, I am generically aware that it's possible to ride a train from BWI to New Carrollton or downtown Washington, and then proceed on the metro to wherever. But I've never done it, and have no idea how efficient/frequent the service is or how expensive. Anyone have any advice on the merits of rail vs. other modes going southwest from BWI? In my particular case, College Park via rail represents a significant detour in miles (going into washington by amtrak, marc, or orange line, back out on green line) but may still be break-even in time if traffic is bad, and a considerable cost savings, compared to the $50-ish ride direct from BWI to College Park. Words of wisdom would be welcome.