At times during last week's House-Senate conference on the 1991 transportation appropriations bill it seemed as if someone had forgotten to tell members there was a budget crisis.

During a session chaired by Sen. Frank R. Lautenberg (D-N.J.), the bipartisan conferees approved a $2.5 billion, 18.8 percent increase in federal aid to states for highway and bridge construction; channeled $125 million to the electrification of the Northeast rail corridor between New Haven and Boston; and directed the Department of Transportation to spend more than $30 million to study magnetic levitation trains and "intelligent" cars.

They threw in $1 million to develop a "national transportation policy" on bicycling and walking, noting the potential in energy savings and reduced traffic congestion. "You have to leave room for the new, with some uncertainty of where it leads you," said Rep. Martin Olav Sabo (D-Minn.), a sponsor of the bike proposal.

Such scenes are part of a little-noticed story in this month's budget debacle. While defense spending and automatic benefits such as Medicare and farm programs were slashed by the deficit-reduction agreement between the White House and Congress, the Appropriations committees came away with a small windfall.

Predictably, a healthy chunk of it is going to home-state projects of influential committee members. But the fattened appropriations coffers have also allowed the committees to address new issues and start rebuilding old, proven programs that fell on lean times in the Reagan years.

There is money to study global warming and the health impact of high power transmission lines on humans. The budget of the Environmental Protection Agency is to grow by 19 percent, and the space program was restructured to provide more money for probes to monitor the Earth's ecology.

The 13 major national laboratories that are the core of American scientific prowess got increases of as much as 18 percent. Despite talk of austerity, the appropriators found money to continue funding the exotic and the futuristic, from the Search for Extraterrestrial Intelligence to the CRAF-Cassini probes that will meet up with a comet and visit Saturn later in the decade.

There will be much more money for some of the old meat-and-potatoes programs: a $554 million, 27 percent increase in the Headstart preschool program; $1 billion more than last year for education programs for the disadvantaged; a commitment to build 10,000 public housing units; and funding for two new Department of Veterans Affairs nursing homes.

The relatively flush position of the Appropriations committees in the final days of the session results from the tenacity and power of a few influential members during last summer's budget negotiations, and the relentless spending pressures on both parties.

Senate Appropriations Committee Chairman Robert C. Byrd (D-W.Va.) recently described nonmilitary domestic spending as the "little runt pig" of the budget that has been "on the cutting table for 10 years."

The $182.7 billion available in 1991 represents only about 13 percent of the budget, compared with nearly 25 percent in the late 1970s. Its share of gross national product has slipped, too, from around 6 percent to close to 4 percent.

This is the "discretionary" pool of money that Congress has to finance the nondefense operations of government and most federal support for science, health, space, environmental protection, waste cleanup, health, education, law enforcement and infrastructure.

In last summer's deficit-reduction negotiations, Byrd reportedly fought relentlessly to prevent a further raid on this domestic pot. In private and public, he gave the same speech: "It's time we started spending some money on this country."

That view is reflected in the deal that emerged from the summit and that is being revised on Capitol Hill. The deficit will be reduced by $500 billion over the next five years, through tax increases and cuts in automatic benefit programs. But none of the cuts will come from the pool of "discretionary" domestic funds controlled by Byrd and his House counterpart, Appropriations Committee Chairman Jamie L. Whitten (D-Miss.).

This pool of money will grow at the inflation rate until fiscal 1994, when the appropriators will be free to increase it further by "raiding" defense accounts under their control.

The $182.7 billion available for 1991 already reflects a small "peace dividend," because the summiteers allowed the appropriators to reallocate the defense cuts to the domestic side. The domestic pot for 1991 is about 10 percent bigger than the $166 billion in 1990, though inflation eats away some of the increase, as does a special $7.5 billion expenditure to renew expiring leases on subsidized federal housing.

The package before Congress also protects the Appropriations committees from having to absorb the costs of Operation Desert Shield in the Persian Gulf. It will be paid for in a special appropriation next year.

Neither the White House nor congressional Republicans had much heart for further cuts in domestic accounts, sources said. The White House wants to channel more resources to the National Aeronautics and Space Administration, whose facilities are concentrated in Sun Belt states that could be important to President Bush's 1992 reelection. Meanwhile, most House and Senate Republicans agree with Democrats that government needs to invest more in the nation's infrastructure, education and industrial competitiveness.

The resulting appropriations bills contain more money for space. But there is also more for social programs that slipped far down the priority ladder during the Reagan era.

Few have come away fully satisfied. Lobbyists say there is still far too little money for education, health, environmental cleanup, consumer protection and alternative energy. Money for the atom-smashing Superconducting Super Collider in Texas was cut at the last minute by $75 million and the allocation for the space station was reduced sharply. The space station cuts drew a protest from Sen. Jake Garn (R-Utah), who has flown on a shuttle mission.

But the $243 million for the super collider is still more than was provided in 1990, and NASA's budget was increased by 13 percent. "It's not as if we're gouging them," said Sen. Barbara A. Mikulski (D-Md.).

Moreover, the appropriations system adjusts, if slowly. For example, the new batch of appropriations bills contains more than $2 billion for research and treatment of AIDS, not even recognized as a disease in 1980. Late Friday, conferees added another $67 million for screening, early intervention and grants to cities hardest hit by the AIDS epidemic.

Yet the appropriations process is messy and this year has once again raised questions about the way the U.S. government sets priorities. The battle over the funding of the AIDS care bill signed by Bush in August has pitted AIDS sufferers on the one side against cancer patients, the elderly and the education community on the other. All are financed by the same appropriations bill.

As old programs battle new ones, pork-barrel projects claim their share. Language in one bill, promoted by Sen. Ted Stevens (R-Alaska), could lay the groundwork for the University of Alaska to acquire a computer to study ways to capture energy from the aurora borealis, or northern lights.

Problems such as homelessness and drugs, funded to the hilt when they were visible, fashionable issues, continue to incur large obligations on appropriations accounts even though they have faded from headlines.

Last week, House-Senate conferees used the purse to address the latest Topic A. They approved $159.5 million for investigating and prosecuting savings and loan fraud, more than triple the White House request.

In other areas, good causes seem to require political clout to move along. Last week, for example, Senate conferees succeeded in boosting funding of the 1989 oil spill prevention and response act from the $11.2 million sought by the White House to $52.2 million.

The key was the New Jersey-New York team of Sens. Lautenberg and Alfonse M. D'Amato (R-N.Y.). Lautenberg is chairman and D'Amato is ranking Republican on the Appropriations transportation subcommittee. They assured that the extra money was approved. Among other things it will be used to establish a new Atlantic Coast "strike team" in the Coast Guard to deal with oil spills in New York/New Jersey harbors and the Delaware River.

Also included in the transportation bill was $3 million for a New York-New Jersey consortium that is developing electronic toll collection systems and signs that can vary their messages to drivers. To some, those are examples of a marriage of good politics and good policy, and explain why appropriations bills have such broad constituencies.

Others suggest that the small windfall allowed appropriators to avoid tough choices while attempting to satisfy every constituency and loading up on pork. An aide noted that the new VA nursing homes and public housing construction will mean rising operating costs later.

"We're all wanting to add the new {projects and programs}," said Sen. Pete V. Domenici (N.M.), ranking Republican on the Senate Budget Committee. "We could decide there are some programs that are worth more than others."

But Domenici has been no more willing than other senators to allow cuts in programs affecting his state. As a member of several Appropriations subcommittees, he helped protect research funds for Los Alamos National Laboratory and supported a $211.6 million allocation to improve U.S. facilities along the U.S.-Mexican border, including several in New Mexico.