WASHINGTON, Sept 21 (Reuters) - U.S. President Joe Biden and British Prime Minister Boris Johnson discussed the dangers of climate change and bantered about the joys of rail travel on Tuesday during an Oval Office meeting aimed at highlighting the U.S.-British alliance. Biden told the visiting prime minister, who once worried his warm relationship with former President Donald Trump would hurt relations under the U.S. Democratic leader, that he looked forward to coming to the United Kingdom for a conference on global warming later this year. "It"s fantastic to see the United States really stepping up and showing a lead, a real, real lead," Johnson said, referring to the issue of global warming. Under Biden, the United States has renewed pledges to cut greenhouse gases and promised to finance projects to combat climate change. Johnson took the Amtrak train from the United Nations General Assembly in New York to Washington for the meeting. "They love you," Johnson said to Biden, seemingly referring to the U.S. railway staff. Biden was a regular train commuter for over 30 years. "We"re going to talk about trade," Biden said when asked about a potential UK-US trade agreement, which would be of great significance for post-Brexit Britain. Johnson first met Vice President Kamala Harris, who said the United States and Britain are more interconnected than ever before. Tackling the pandemic, dealing with climate change and upholding democracy around the world remained top priorities for both countries, Harris said. Johnson praised the U.S. military"s role in the "Kabul airlift" and thanked the U.S. government for lifting a ban last year on imports of British beef imposed after an outbreak of mad cow disease. "I want to thank the U.S. government, your government, for the many ways in which we are cooperating now, I think, at a higher and more intense level than at any time I can remember," Johnson said. Johnson"s team regards the visit as a triumph, demonstrating that Britain can thrive on the world stage after its divorce last year from the European Union. It comes amid a U.S. rift with EU rival France, in which Britain played a crucial part. A submarine deal the United States and Britain recently announced with Australia came at France"s expense, prompting France to withdraw its ambassadors to the United States and Australia and cancel a defense meeting with Britain. read more France continues to see Britain as the junior partner in the long-running "special relationship" between the United States and Britain, some say, years after former British Prime Minister Tony Blair was ridiculed for supporting U.S. President George W. Bush"s invasion of Iraq in March 2003.