Ridership on the PATCO commuter rail line has reached its highest level in more than seven years, as higher gas prices and bridge tolls helped drive passengers from their cars to the train.

Weekday ridership topped 40,000 trips in the first week of October, PATCO general manager Robert Box said yesterday. The last time it was that high was in early 2001.

"That's a real milestone," Box said at yesterday's monthly meeting of PATCO's parent, the Delaware River Port Authority. "And we have not seen any drop-off with gas below $3 a gallon. We're working real hard to keep those customers."

Average weekday ridership through September has been about 36,100 this year, the highest since 2000. The record for weekday ridership was set in 1990, at 41,340.

The weekly average ridership this year is 196,124 trips, up more than 8 percent from last year's weekly average of 181,166 trips.

At the same time, traffic is down on the Ben Franklin, Walt Whitman, Commodore Barry and Betsy Ross Bridges.

Also yesterday, the DRPA board approved borrowing $510 million through the issuance of revenue bonds. The money will be repaid with the proceeds of bridge tolls, which were raised last month to allow the borrowing.

The borrowed money will be spent on repairs and improvements to the four DRPA bridges and its fleet of PATCO railcars.

The interest rate on the bonds will be as high as 7.5 percent for fixed-rate bonds, and as high as 15 percent on variable-rate bonds.

DRPA will borrow an additional $437 million in the next several years, to be paid for with more toll increases. A toll increase is set for 2010, with bridge tolls to go from $4 to $5 and PATCO fares to rise 10 percent. Beginning in January 2013, increases tied to inflation are to be imposed on fares and tolls every two years.

The current borrowing, unlike some in the past, cannot be spent on economic-development projects, chief financial officer John Hanson said yesterday.

In the last decade, DRPA used $375 million in toll revenue to help fund economic-development projects such as the Kvaerner Philadelphia Shipyard, Lincoln Financial Field, the Kimmel Center, the National Constitution Center, the Camden Riversharks' minor-league baseball stadium, the National Museum of American Jewish History on Independence Mall, and, most recently, a soccer stadium complex on the Chester waterfront.

That spending helped push the port authority $1.2 billion into debt. It now spends $100 million a year, or about 42 percent of its operating budget, to pay principal and interest on that debt.

Contact staff writer Paul Nussbaum at 215-854-4587 or pnussbaum@phillynews.com.