The Bruins have come face-to-face with a runaway train at a pretty bad time. Boston, which has lost three of its last four games, is in Tampa on Thursday for a tilt with the Lightning, who sit atop the NHL with 43 points. After an abysmal showing Tuesday night against the Florida Panthers, Bruins head coach Bruce Cassidy shook up the lineup during Wednesday’s practice, and is expected to roll with those changes against the Bolts. Joakim Nordstrom will move up to the second line — which was a move that worked out well earlier in the season. Sean Kuraly and David Backes will hop up to the third trio alongside Danton Heninen,