METRO SEEMS to be winning friends in Congress. Perhaps the most important new support this year has come from Rep. William H. Natcher (D-Ky.). As chairman of the House Appropriations Subcommittee on the District, Mr. Natcher has spent many a painstaking hour obstructing Metro's requests for subway money. What annoyed him as much as anything, apparently, was the way in which Metro officials used to do their arithmetic; they were maintaining that the proposed 97-mile system could be built for $2.5 billion. Mr. Natcher was predicting $4 billion to $5 billion. Today, thanks to inflation and the construction delays caused by Mr. Natcher's past delays, Metro's official forecast for a 100-mile system tops $5 billion.

The big difference now is that Mr. Natcher is impressed with Metro's new leadership. "I like the way you answer questions," Mr. Natcher said to Metro general manager Theodore C. Lutz at a hearing last month, noting that in the past "we've had a difficult time getting answers to our questions." He has endorsed a proposed federal subsidy to pay interest on nearly $1 billion in construction bonds.

While Mr. Natcher's subcommittee does not have jurisdiction over the enactment of legislation to adopt an 80 per cent federal subsidy, his support is important on Capitol Hill. Indeed, the House Appropriations Subcommittee on Transportation already has voted to grant a federal subsidy of the interest payment. The full committee is scheduled to review the legislation on May. 26, when, we hope, it will again win approval.

The success of Mr. Lutz with Mr. Natcher is yet another sign that Metro's new general manager has been turning things around for the better. His reorganization of the staff, his willingness to consider modifications in the overall subway plan and his sense of responsibility to both Congress and the system's riders has been refreshing - and so far, the dividends have been handsome.