A look at what happens...

...after state officials leave town following an announcement involving a big check:

But before an actual design of the estimated $50-million-to-$55-million interchange and surrounding development is finalized, officials from Andover, Tewksbury and Wilmington will wait for early environmental and engineering work to get under way in the area, which is located in the southern-most portion of town between the Dascomb Road and Route 125 exits on I-93.

“There’s going to be a reality check,” said Bob Halpin, president of the Merrimack Valley Economic Development Council. “This will be a process now where real engineering is done and cost constraints and physical restraints will kind of lead people to a final design.”