THE CITY solicitor's office played a sly move when it raised the civil-rights implications of SEPTA's proposal to eliminate transfers as part of a cost-cutting strategy.

And we mean that in the best possible way.

In a lawsuit filed last week, the city claims that SEPTA's elimination of the paper transfers has the net effect of increasing fares for city riders by up to 80 percent, far more than the 11 percent that SEPTA says its fare boosts averaged. That's because those riders paying cash and requiring a transfer - primarily poor and African-American city riders - will have to pay double the fare once the transfers are eliminated. Meanwhile, the smaller fare boosts favor riders of the regional rail lines.

The city communicated its concerns to the Federal Transit Administration; the FTA quickly followed with a letter to SEPTA officials, demanding that it provide an analysis of the impact of the proposed changes on the city's minority and low-income populations.

That's a reasonable request. In fact, we'd say that it's a reasonable expectation that a large transit authority would have done such an analysis before finalizing its cost-cutting strategies.

And it's more than reasonable to expect the agency to provide some economic rationale for making the proposed changes. Until recently, we have taken it on faith that SEPTA's plan for eliminating the transfers was the result of detailed financial reports and analysis of all options. But SEPTA officials' lack of numbers that spell out how it arrived at the cost-cutting gives us pause. Just how did it arrive at its decision? Why was it necessary to make the transfer change now, rather than later, when it plans to phase in a smart-card system?

Apparently Common Pleas Judge Gary DiVito had similar questions when he told SEPTA last week, and then again this week, to keep the transfers in effect for the time being. SEPTA officials have 30 days to provide the analysis the feds are asking for. Their initial reaction to the FTA letter was to squawk that the federal rules weren't in effect when they were determining their rate changes. But why wouldn't they have done that analysis as a matter of course? No one claims it's easy to balance social needs and the economic demands of running a healthy enterprise - just ask PGW - but with the kind of public funding that SEPTA gets, it's clear it needs to be reminded of how important that balance is.*