Walter F. Mondale today intensified his call for wayward Democrats to come home, saying of President Reagan's planned whistle-stop tour aboard Harry S Truman's old railway car in Ohio Friday, "He may be on the right car, but he's on the wrong track."

"Let's get it straight," Mondale told a lunchtime throng of more than 10,000 in front of the statehouse here. "Ronald Reagan is no Harry Truman . . . . He should spend less time impersonating Truman and more time listening to what Harry Truman said."

The Democratic presidential nominee also decried what he termed Republican "grave-robbing" that he said was most recently symbolized by a White House ceremony honoring Eleanor Roosevelt, who would have been 100 years old today.

"You don't honor Eleanor Roosevelt by cozying up to the racists in South Africa and the dictators in Latin America. You honor her by standing up for human rights around the world," Mondale said.

"You don't honor Eleanor Roosevelt by fighting the Equal Rights Amendment. You honor her by ratifying it and by electing Geraldine Ferraro vice president of the United States," he said.

Today's speech was laden with quotes from Democratic presidents John F. Kennedy and Truman and humorist Will Rogers. Mondale said Reagan could be described aptly in the words with which Rogers characterized Herbert Hoover: "It's not what he doesn't know that bothers me. It's what he knows for sure that just ain't so."

Mondale then listed statements Reagan has made as president, adding about each, "It just ain't so." Included were claims that nuclear missiles could be recalled after launch, that Soviet bombers and submarines are not equipped with nuclear weapons, that two-thirds of the U.S. military budget is spent on salaries and pensions and that federal budget deficits do not result in higher interest rates.

"You may think you can fool Democrats just by riding on Harry Truman's train," Mondale said, adding as the crowd joined the refrain, "but it just ain't so."

"And, Mr. President," he said, "you may think you're gonna win this election, but it just ain't so."

Today's strongly partisan rhetoric was laced with appeals to traditional Democratic concerns that included jobs, education, civil rights and tax equity.

Mondale strategists are hoping that his performance in last Sunday's debate with Reagan will help make these themes especially resonant during this week's swing through six key industrial and agricultural states of the Midwest and Northeast.

Mondale trails in all six, including his native Minnesota.

These themes have been coupled with an assault on Reagan on the "fairness issue," principally involving Social Security and Medicare, programs long identified with the Democratic Party.

Mondale also is appealing to independents, emphasizing at each stop the Republican Party's alignment with the Rev. Jerry Falwell, head of the Moral Majority.

"If you pull their lever," Mondale said today, "you'll be handing over the Supreme Court to Jerry Falwell, who wants to run the most private questions of your life."

With Reagan more on the defensive since the debate, Mondale is trying to cast off the political image, as some foes have put it, of "Minnesota Fritz and the Party of Gloom."