The latest congressional plan to rescue crumbling Union Station passed the House without opposition yesterday and now goes to the president. The plan would repair the 74-year-old Beaux Arts edifice, make it a train station again and seek development of shops and offices in and around it.

The bill, already passed by the Senate, would make available at least $80 million in government funds and is supported by U.S. Transportation Secretary Drew Lewis, despite his inability to win some technical changes.

For the administration, a strong selling point was that the program would be financed almost entirely by previously appropriated government money or private funds. The only new government money in the bill is up to $275,000 per year for six years to buy out a lease and assume ownership from private railroad concerns that own the station.

The station, which once ranked among the world's busiest rail gateways, came to public attention last February when rains flooded its floors and sent huge chunks of plaster falling from the ceiling. The building was closed as a safety hazard.

It is now officially known as the National Visitor Center, operated by the Department of Interior. In 1968, in an earlier attempt to preserve the station, Congress authorized massive renovation to turn it into the center. Trains were relocated to a new station in back. But the building never caught on in that role and continued to deteriorate structurally.

The plan now before Reagan calls for completion of $8 million in roof repairs that Interior has already begun and authorizes spending of $40 million in interstate highway funds to complete a parking garage that was last worked on in 1976.

Two detailed studies would be conducted under the plan, one to determine repairs the building needs and another to examine the feasibility of commercial development. The plan would formally eliminate the Visitor Center and transfer control of the building to the Department of Transportation.

If the repair survey found the building could be restored, the government would be authorized to do further work on it, drawing up to $29 million from an ongoing $2.19-billion capital program to upgrade rail lines along the Northeast Corridor and other funds from other programs, if needed.

If commercial development is found to be feasible, the plan provides for DOT to sign long-term leases with private firms. It does not spell out what type of development would be favored, but shops, offices and hotels have been suggested.

However, the plan does specify that whatever development scheme is decided upon, Union Station must also be a rail station, providing baggage handling, ticketing and transfers to buses. The new structure behind it where passengers now embark would be torn down.

Testifying on Capitol Hill recently, Lewis sought authority to sell the station to private developers if necessary. However, congressional supporters of the bill argued that Union Station is a national monument and should remain in public hands.

The plan's sponsors hope that development of the station will revitalize the surrounding neighborhoods. Several real estate companies have expressed interest in the plan, according to a Hill aide who worked on the bill extensively.