The New York Federal Reserve officials tasked with prying interest rates off the floor have been meeting with bankers and traders to plot how best to do it, amid deep uncertainty over how much control they will really have over short-term lending markets. With the U.S. central bank expected to raise rates later this year, Simon Potter and his team of market technicians have the tricky job of implementing higher rates using some new and lightly tested tools as well as some that may not work as well as in the past.