In barnstorming the state earlier this month to sell his $222 billion master plan to rebuild California’s creaky infrastructure, Gov. Arnold Schwarzenegger chose a noisy underpass construction site in El Monte for one of his photo ops.

The governor’s message? Even a concrete tunnel is beautiful if it makes things run smoother.

The underpass is a sliver in a $950 million project to expedite east-west train movement and lighten vehicle tie-ups along a 35-mile freight corridor through the San Gabriel Valley.

While most people have probably never heard of Alameda Corridor East (ACE) in an era of sleek light rail lines, it is the type of no-frills public works effort where global economics and suburban quality-of-life either are balanced or continue clashing.

There’s not much choice. Southern California’s position as the clearinghouse for goods shipped through the ports of Los Angeles and Long Beach on their way across the country is surging with no letup in sight.

By 2020, officials expect $314 billion worth of products a year will thunder along the original Alameda Corridor, a 20-mile trenched train corridor from the ports to East LA. It opened three years ago.

Even before it opened, freight traffic through the San Gabriel Valley produced congestion and complaints. Drivers sometimes faced agonizing waits for trains to pass, or dangerously tried to beat them across the tracks. It hampered some 911 emergency responses, too.

With more trains pounding along the Union Pacific right-of-ways and a population boom expected to add millions more people here, doing nothing could eventually translate into a threefold delay for cars and trucks at local rail crossings, ACE officials have warned.

As much as 40 percent of all US imports – most from China – now come through LA-area ports. It was that realization that made Valley cities in the mid-1990s agitate for traffic relief around the freight lines.

“We have 70 to 90 trains,” running through here a day, “and that exceeds what we originally projected,” said Sharon Neely, ACE’s director of transportation policy. “It might be 160 trains a day by 2020.”

ACE will tackle the train-versus-car impasse with metal, concrete, and microchips to eliminate or slash vehicle wait-time. The two Union Pacific lines at the heart of the project lie near the San Bernardino (10) and Pomona (60) freeways.

Contractors are building vehicular bridges and digging tunnels at every 20 rail crossings and making safety improvements at another 39. Four crossings will be dismantled altogether. Roadway widening and computerized traffic-signal control measures are also part of the package.

The side benefit is cleaner air. By keeping cars and trains moving efficiently, it will cut 221 tons of smog-forming pollutants annually.

Schwarzenegger’s blueprint to modernize California’s roads, schools, ports and other public places has drawn some political heat because of budgetary and environmental concerns. The governor, nonetheless, singled out ACE as something state money should bankroll. Before him, county Supervisors Mike Antonovich and Gloria Molina championed it.

Neely said ACE has secured $530 million of its total budget so far, with the state and the federal government each promising to finance 40 percent. She hopes the latest federal transportation bill will haul in another $70 million, plus new state funding from the governor’s plan.

Valley cities had wanted Union Pacific to pony up a good chunk, too, but it only contributed the legal minimum: $12 million. The twin ports, which kicked in roughly $400 million to the original Alameda Corridor, have given nothing because officials there contend the ports have “zero impact” on the San Gabriel Valley, Neely said.

“The cities in the beginning asked for a partnership with the railroads and ports, but they realized it wasn’t going to happen,” she added. “The [railroads] see grade separations as no benefit to them.”

At one point, the cities discussed suing the ports but in the end chose not to litigate, Neely said.

A Union Pacific spokesman said the company assesses the gains it would accrue from a project like this in calculating how much to contribute.

“This would have more benefit to the public than private,” Davis said.

A joint venture led by Bechtel Infrastructure and Korve Engineering is managing the construction. Originally set to cost $912 million, the tab has swelled roughly $38 million because of inflation and higher cost of materials, Neely said. The job should be completed by 2010, two years behind the original date.

Korve, an Oakland-based outfit, conceived the idea after doing a mobility analysis for the San Gabriel Valley Council of Governments, a 31-city joint powers authority.

The council’s seven board members, along with an ex-officio representative from San Bernardino, provide oversight of the small construction authority that manages the day-to-day work.

ACE officials and others expect to some day extend the corridor into Orange, Riverside and San Bernardino counties, bringing the entire line to 282 miles at a cost of $2.4 billion.