California’s bullet train planners Wednesday cracked open the flood gates for bidders expected to rush in seeking billions of dollars in construction work projected to start next year.

Requests for expressions of interest were sent to thousands of large and small contractors worldwide that may want a piece of the first phase of the $43-billion network that is supposed to connect the Bay Area and Southern California with trains running up to 220 mph.

Officials portrayed Wednesday’s announcement as a milestone for one of the largest public works project in the nation’s history, an endeavor that could ultimately create hundreds of thousands of construction and other jobs.
  
Work on the first $5.5-billion section of track, from north of Fresno to the outskirts of Bakersfield, is scheduled to begin late next year. Wednesday’s solicitations were a step toward issuing contracts for that work.