Amtrak has announced a 7 percent increase in regular fares and accomodation charges on most routes, to take effect July 15.

The fare boost is the second this year - rates went up 6 percent in March - but Amtrak said the higher charges comply with both the administration's anti-inflation guidelines and Department of Transportation standards, designed to offset rising fuel costs and to help shrink Amtrak's budget deficit.

For Washington-to-New York riders, the new fare policy means a $2 increase on both Metroliners and conventional trains, while round-trip excursion rates will rise to $37 from $34.70.

Despite the increase, only $4.5 million of new revenues are anticipated - about half the overall diesel fuel cost increases recently. In the past six-month period, fuel costs have jumped $7 million, according to Amtrak officials.

"We don't anticipate a big reaction by riders," said John Jacobsen, an Amtrak spokesman. "It's not a big increase and I think people are aware of the pressure we're under by Congress to get a handle on our deficits."

Both Congress and DOT have established revenue-to-cost ratio levels of 44 per cent by fiscal 1983 and 50 percent by the end of fiscal 1985. Currently, Amtrak revenues cover only 37 percent of costs.

Amtrak ridership across the country has increased substantially in recent months due to gasoline shortages. In the heavily traveled Northeast corridor, however, ridership is up just 2 percent during a period when Amtrak has cut back total car usage to overhaul old units and is undergoing a major track improvement program in the region.

"We're doing a record business with less capacity," Jacobsen said yesterday, Nationwide, 100 cars have been called in for repairs when Amtrak is turning away 750,000 people a month.

In a related development, the Air Transport Association has objected to the General Services Administration's recent arrangement with Amtrak establishing a 20 percent discount on all official government travel on the Washington-to-New York Metroliner.

The airline association charged that the move was discriminatory and in conflict with "sound public policy, basic economics and government efficiency."

"I'm not surprised," said Jacobsen. "We're luring some of their business away but there's nothing to prohibit airlines from offering discounts."

He noted that GSA's move followed studies indicating that some government officials taxied to the Baltimore airport, took a plane to Philadelphia and taxied the rest of their destination.

"The GSA is recognizing that executives can work on a train but they can't work in a taxi cab," said Jacobsen.

However, he noted that the main issue between the airlines and the railroad is Amtrak's highly publicized federal subsidy. "Just because it's visible, it's controversial," Jacobsen said.