Amtrak President David Gunn said the railroad can keep running into next week, but the cash situation will become critical next Thursday -- the Fourth of July -- or Friday.
Independence Day is traditionally a busy travel day.
Gunn said without a resolution to Amtrak's $200 million budget gap, the system could begin shutting down by recalling its long-distance trains. A system wide shutdown would take four days.
Transportation Secretary Norman Mineta said a solution was "very, very close" and could be solved by Wednesday, but he offered no details.
One option is a loan guarantee by the government. Another is an appropriation by Congress.
Amtrak routes include stops in four Alabama cities and in Chipley, Florida.