After weeks of ardent courtship by Democratic presidential candidates Sens. Hillary Rodham Clinton and Barack Obama, voters in Western Pennsylvania turned out in large numbers that nevertheless fell short of some election officials' ambitious predictions.

Voter turnout was about 50 percent statewide -- or about 4 million people from all parties -- for yesterday's Democratic primary. That is more than double the 21 percent who voted in the 2004 primary.

The turnout was slightly higher, at about 54 percent, in Allegheny County, according to state and local election officials. Despite the large numbers of voters, many of whom were newly registered, only a few scattered problems were reported.

Political observers had predicted that strong public interest in the Democratic primary could approach records set in 1980 and 1988, when 68 percent of Democrats voted.

Still, yesterday's vote and Pennsylvania's newfound primary status represented a historic day for many voters. A steady stream of moms and dads, college students and retirees, office workers and construction workers kept poll workers busy until polling stations closed at 8 p.m.

Erika Way, weighed down by the exhausted 4-year-old son she carried into her polling place at Lincoln Elementary School in Mt. Lebanon just after 7 p.m., said her worries about the eroding economy and the war in Iraq drove her to vote in the Pennsylvania primary for the first time.

Former President Bill Clinton spent more than an hour at the school earlier in the day -- about 20 minutes discussing his desire to make significant changes to the No Child Left Behind Act -- stumping for his wife. Nevertheless, Ms. Way, 31, said she voted for Mr. Obama because she thinks he can reach across party lines and cultural divisions.

"I try to think about it internationally and I think he can relate to different countries and make a statement that America is open to different races and backgrounds," she said.

Pedro Cortez, secretary of the Pennsylvania Department of State, said that while there were some sporadic problems at the state's 9,260 polling places, such as a few that didn't open right at 7 a.m. and a few problems among the state's 25,000 voting machines, "We had a good election."

He said the voting at college campuses went well, considering that there were many first-time voters who had to show identification.

The combination of primary day and finals week made for a frenzied atmosphere on campus at the University of Pittsburgh, with many students supporting Mr. Obama just one day after his rally drew 10,000 supporters to the Petersen Events Center.

"I felt like if I didn't vote I was going to die," said junior Brittany Jones, who voted for Mr. Obama. "The Barack people were calling me. There are people on the street. There's sidewalk [chalk writing] everywhere. There's just a lot of pressure. I think I would have felt bad if I didn't vote."

Throughout Western Pennsylvania, election officials were surprised that the voting was largely smooth and steady.

"Considering the Democratic primary race between Senators Obama and Clinton, I thought we would definitely draw more voter participation than we're seeing," said Dorene Mandity, director of the Beaver County Bureau of Elections.

"You sure can't blame the weather," she said, referring to the day's sunny skies, after she lowered her voter turnout expectations from perhaps 60 percent to no more than 50 percent. Prediction of a record turnout in Butler County by elections director Regis Young also were diminished by mid-day.

Some rural areas of Washington County reported heavy turnout, but an elections judge in Washington, Pa., was amazed that fewer than one-fifth of registered voters had shown up in the heavily Democratic district by late afternoon.

"This is all anyone talked about," said Lisa Spossey-Gorby, the surprised official. "Now we're like, 'You've got to be kidding me.' "

Mark Wolosik, director of elections in Allegheny County, had forecast a 60 percent turnout among Democrats. Although turnout fell short of that number, there were pockets of higher-than-usual activity in black communities such as Homewood.

At the Homewood House senior citizen apartment building, the 100 voters there by noon represented about twice what would have been normal at the time, said elections judge Shirley Wheaton.

"I think [Obama's] drawing a lot more people out," especially younger voters, she said.

In Squirrel Hill, Jason Harland, 31, was among those voting at Pittsburgh Colfax K-8 school. He normally would not bother with a primary election but showed up for this one.

"This is different. For once, Pennsylvania actually matters," the Obama supporter said.

While turnout may have been less overwhelming than some expectations, so, too, were the number of problems associated with the surge of newly registered voters.

The state's Democratic Party had 317,000 more registrants than last fall due to high interest in the presidential race.

Allegheny County voters encountered problems with computerized voting machines that malfunctioned, confusion over whether they had the right to vote in the primary and misdirections to voting places, among other concerns. Mr. Wolosik said there were machine problems requiring use of emergency paper ballots in North Braddock, Banksville, Swissvale and McCandless, which he attributed primarily to errors by workers in processing the machines. Voters also told the Post-Gazette of problems in Wilkinsburg and Wilkins.

As a whole, however, Mr. Wolosik said fewer problems were reported than in other recent elections when the touch-screen voting machines were newer.

More than a few voters registered as independent showed up at the polls, believing they could vote in the Democratic primary, which is permissible in some states.

"Why didn't anyone tell me before?" said a disappointed Sean Weir, 32, of Bloomfield, when poll workers instructed him his presidential vote would have to wait until November.

"There were people calling who couldn't understand why they couldn't vote in this primary, when they say they vote every election," Mr. Wolosik said, acknowledging confusion among those with no party affiliation.

While Mr. Weir's potential vote for Mr. Obama was nullified, across the state in West Philadelphia, 85-year-old Mary Hilferty had herself wheeled into a firehouse on a gurney to vote, directly after dialysis treatment.

"I'm here for Hillary, and I hope everyone else is, too," she said. "[Senator Clinton] has made some goofy mistakes, but she's a woman and she thinks like a lady."

Within the city of Philadelphia, Obama signs, stickers and T-shirts seemed to be everywhere, while support for Mrs. Clinton was more visible in the suburbs. Southeastern Pennsylvania was a key battleground in the state because its five counties include 35 percent of the state's registered Democrats.