The first four of the 75 long-awaited commuter rail coaches being built for the T by South Korean firm Hyundai Rotem are finally in the MBTA’s possession. That does not mean customers will get to ride in the modern double-decker cars anytime soon, though they may spot them on test runs.

The four “pilot coaches” were delivered the morning after Election Day to the MBTA’s Boston Engine Terminal. (That’s the massive purple and blue commuter rail maintenance hangar visible from Interstate 93 in East Somerville.) The double-deckers are the first production vehicles that followed the prototypes, and they will be put through extensive testing before the rest are mass-produced.