During the fight over tax reform, the Maryland House delegation earned the reputation in Congress as the staunchest defenders of federal employe benefits.

And on a wide range of other issues, from Amtrak to regional airports to international trade, the Maryland delegation drew the battle lines on fights that are expected to heat up even more in 1986.

The Maryland House members were instrumental in blocking the first attempt to vote on the massive tax overhaul bill, which ultimately passed the House in December. They opposed the measure because it changed pension tax rules for federal employes.

Federal retirees currently have a tax-free period, ranging from 18 months to 3 years, before they have to start paying taxes on pensions. Under the tax bill, that tax-free period would be eliminated.

Although total taxes paid on pensions would not increase, the change would create problems for federal workers who have anticipated a tax-free period in planning their post-retirement finances, according to Rep. Steny Hoyer (D).

The entire Maryland House delegation first voted to block consideration of the bill. After prodding from President Reagan and the House Democratic leadership, however, Reps. Helen Bentley (R), Marjorie Holt (R), Beverly Byron (D) and Parren Mitchell (D) reversed themselves and voted to allow the bill to come to the floor, where it passed on a voice vote. The Senate is expected to consider tax reform this year.

Concern over the impact on federal employes also prompted some Maryland legislators to vote against the Gramm-Rudman-Hollings automatic deficit reduction bill. Unless taxes are raised, the measure is expected to result in the firing of thousands of federal workers in the Washington area, as federal agencies are required to cut back.

Gramm-Rudman opponents, including Sen. Paul S. Sarbanes (D) and Rep. Michael D. Barnes (D), also warned that the automatic budget cuts could send the country into economic chaos. Byron and Rep. Roy Dyson (D) were the only two members of the Maryland delegation to support Gramm-Rudman.

With Holt the lone exception, the Maryland delegation also voted for a trade bill limiting textile and shoe imports. Labor unions strongly supported the bill, arguing that domestic textile mills, such as those that used to operate on the Eastern Shore, were unable to compete with cheaper labor overseas and in the South and began closing on a widespread basis in the 1970s.

President Reagan strongly opposed the trade measure and has since vetoed it. Sen. Charles McC. Mathias Jr. (R), chairman of the Foreign Affairs subcommittee on international economic policy, said that he, too, was concerned about the threat of a trade war but that the United States must take firm actions to force other nations to eliminate trade practices unfair to American companies.

Last month, Congress finally passed a massive farm bill that Reagan reluctantly signed. Sarbanes voted for the bill, and Mathias did not vote. Holt voted against the farm measure, while the other Maryland House members voted for it.

Dyson, who represents the Eastern Shore, said the farm bill was the number-one topic of discussion whenever he returned to his district last year. He said that although the foreclosure rate on the Eastern Shore has not been as high as in other areas of the country, an "alarming" number of Maryland farmers are unable to make a profit.

The entire Maryland delegation voted to continue the "superfund" hazardous waste cleanup program. Bentley supported a new broad-based tax on manufacturers to fund the program, while the other Maryland House members voted instead to keep the tax burden focused on the oil and chemical industry.

The House approved an amendment to continue the petrochemical industry tax, while the Senate-passed bill contained the general business tax. The House and Senate were not able to work out the differences before adjournment.

The Maryland delegation also led the opposition to a proposed transfer of National and Dulles International airports, both in Northern Virginia, from the federal government to a regional authority. The regional authority would be able to float bonds and invest far more money in the airports than the federal government can, according to Virginia officials.

The Reagan administration supports the proposal, saying that the federal government should not be in the business of running commercial airports.

But Maryland officials fear that the plan could give the Northern Virginia airports an unfair competitive advantage over Baltimore-Washington International Airport. The Senate is expected to vote on the proposal in the next few months. The House has not yet considered the bill.

Maryland legislators also opposed efforts to reduce funding for Amtrak and mass transit, and were key players in the efforts to enable port dredging in Baltimore and other ports to begin this year.