By David Shepardson and Lisa Baertlein WASHINGTON/LOS ANGELES (Reuters) – The U.S. House of Representatives plans to vote Wednesday to block a potential a U.S. rail strike after President Joe Biden warned of the dire economic consequences of a rail disruption that could happen as early as Dec. 9. Biden had warned Monday of a catastrophic economic impact if railroad service ground to a halt, saying up to 765,000 Americans “could be put out of work in the first two weeks alone.” U.S. House Speaker Nancy Pelosi said lawmakers will vote Wednesday to impose a tentative contract deal struck in Septe…