The Gold Line arrives : It’s taken $900 million and 22 years, but on Sunday, light rail comes to the Eastside.

It’s hard to build public transit projects in Los Angeles under the best of circumstances, but the Gold Line light-rail spur from Union Station to Atlantic Boulevard in East L.A., which opens Sunday, has a long and bruising history that seems to have left at least one key backer permanently scarred.

County Supervisor Gloria Molina last month called the line “substandard” and worried that it would be unsafe for drivers and pedestrians, despite the fact that it has been vetted and approved by safety experts. “We all struggled so hard to get this into our community,” she said. “Now, at the end of the day, I feel like I’m being shortchanged on the issues of integrity, safety and confidence.”

On the surface, it was a surprising reaction from Molina, a tireless advocate for her Eastside district who is about to see the opening of a perfectly safe, six-mile light-rail line, a $900-million project that took 22 years from planning to completion. Yet she has never recovered from a process in which what was originally envisioned as a spur of the Red Line subway ended up with only 1.7 miles underground. The subway plans were derailed both because of the enormous price tag and because of public anger over cost overruns and sinkholes during the construction of the Red Line to North Hollywood, which prompted Supervisor Zev Yaroslavsky to sponsor a successful ballot initiative in 1998 that forbade using county sales tax funds for further subway projects. Molina is still upset that after getting a subway built in his Westside district, Yaroslavsky saw to it that none would be built in hers.

Fortunately, Molina’s bitterness doesn’t appear to be shared by her constituents, who mostly seem thrilled about Sunday’s debut. They should be; the Eastside has a large transit- dependent population, and by the end of its first year, the Gold Line is expected to attract 13,000 daily boardings.

Of course, this doesn’t mean the sniping over subways has ended. Not satisfied by a recommendation from the Metropolitan Transportation Authority staff that an eight-mile project along Crenshaw Boulevard should be a light-rail line rather than a less expensive dedicated busway, Supervisor Mark Ridley-Thomas hopes to drum up hundreds of millions more dollars to make it a subway. Meanwhile, the so-called subway to the sea along Wilshire Boulevard -- one of the only parts of L.A. with the density to justify the expense of subway construction -- is constantly under threat from politicians who want to seize its funding for their own projects.

But those are fights for another day. On Sunday, there will be such a thing as a free ride, with the new Gold Line operating all day with no charge. All aboard.