Possible Clues:

• Amtrak train that averages 86 MPH
• Zippy Amtrak train
• Amtrak offering
• Amtrak's fast train
• 98-Down train
• East Coast bullet train
• Speedy Washington-Boston connection
• 150-miles-per-hour Amtrak train
• Speedy express
• Amtrak train often taken by Joe Biden