When Jim Hartnett joined the effort four years ago to bring high-speed rail to California, the project was in danger of going off the rails, with intense opposition mounting in Sacramento and on the Peninsula.

The rail project's price tag had more than doubled from what it was in 2008, when the voters passed a bond to fund the high-speed rail system, and the San Francisco-to-Los Angeles line was facing lawsuits from numerous Peninsula communities and citizen coalitions.

Hartnett, who this week was selected as the new CEO of Caltrain, had been a fixture in the Peninsula politics for well over a decade, having served on the Redwood City City Council for 14 years. But as one of the new faces on the California High Speed Rail Authority, he was charged with turning the project around and bringing the Peninsula on board.

So when high-speed rail officials attended a meeting in Mountain View in November 2011 to discuss their new vision for the rail line, it fell to Hartnett to make the case for what is now known as a "blended system." Under this design, the high-speed rail would share a single set of tracks with Caltrain on the Peninsula segment of the line, rather than have its own set. Hartnett called the new approach a "rethinking of the whole high-speed rail approach."

In some ways, Caltrain's choice of Hartnett to replace its recently retired CEO Michael Scanlon, reflects the growing interdependent of the two train systems. While high-speed rail is leaning on Caltrain for its right-of-way and political capital on the Peninsula, Caltrain is depending on $705 million from high-speed rail funds to pay for the long-awaited electrification of the train tracks, a project with a $1.7 million price tag.

Hartnett has plenty of history with Caltrain, having served on and chaired its board of directors before being appointed by the state Senate to join the high-speed rail authority.

In some ways, he has long bridged the two agencies. In 2009, as a Caltrain board member he spearheaded a memorandum of agreement between Caltrain and high-speed rail. The document specified that the high-speed rail system must be "designed, constructed and operated in a manner fully consistent with the operational requirements of the Caltrain commuter rail rapid transit service and with consideration of the cities on the Peninsula through which the high-speed rail system will be constructed and operated."

The document, he said at the time, "not only puts us at the table, it gives us a position at the table that is unprecedented."

During Hartnett's time on the board, the rail authority made a decision to launch the project in the Central Valley and only later connect it to San Francisco and Los Angeles.

With the focus shifting to Bakersfield, Fresno and Merced, angst about high-speed rail has dropped by several notches in Palo Alto and neighboring cities. Caltrain, meanwhile, is speeding toward the electrification project, which will replace diesel trains with electric ones, and allow the commuter service to increase the number of trains and accommodate more riders.

Now, having resigned from the high-speed rail board, Hartnett will take the helm at Caltrain, SamTrans and the San Mateo County Transit Authority. In a statement, Hartnett touted his experience with high-speed rail as an asset in his new position.

"I will be a strong advocate for Caltrain," Hartnett said in a statement. "I know the High Speed Rail organization well and understand the issues. I always looked upon my role on the High Speed Rail board as ensuring that organization was responsive to Peninsula issues."

According to Caltrain, Hartnett will receive a total annual compensation of $434,661, which includes salary and benefits. This consists of a base salary of $263,000 and additional compensation of $75,000 for managing Caltrain; $25,000 for managing the Transit Authority and $71,661 as an "additional cost of the benefits associated with the position." Hartnett's contract is for a five-year term, and he will start his new position on March 30.

In discussing Hartnett's compensation, Jeff Gee, a member of the Caltrain board of directors, said the agency "deserves the best talent that we can afford, attract and retain."

"The person in this job must be compensated in a manner that reflects the challenges and responsibilities of the position, as well as the expectations of our community and region that this work be performed at the highest level and with the greatest skill," Gee said in a statement. "In today's employment market, we are competing not only with other transit agencies in the United States, but also with transit agencies internationally, as well as the private sector.

"We are fortunate that Jim is willing to take on this daunting task, and leave behind a highly regarded and extraordinarily successful legal practice," Gee said.

In announcing the appointment, Caltrain called Hartnett a "key figure in the reorientation of High Speed Rail to a more collaborative partnership on the Peninsula" and credited him with helping to win "legislative support and funding for the program, specifically working with the Legislature to ensure High Speed Rail's early investment funds include the Caltrain Modernization Program."