Auto-Train Corp. filed a petition for reorganization in bankruptcy yesterday after a promised loan from a Swiss bank fell through under bizarre circumstances.

The Washington railroad asked the federal courts for protection from its creditors while it tries to work out a plan to settle debts of more than $10 million.

Auto-Train Chairman and founder Eugene K. Garfield said the decision to reorganize under Chapter 11 of the federal bankruptcy laws will not stop Auto-Train's round-trip service between suburban Lorton and Sanford, Fla.

"We will definitely keep operating. Our trains will continue to run," said Garfield, who started the company 10 years ago on the premise that passenger trains could be run profitably if they provided a unique service.

"It was a long, hard struggle to make it work," he said. "We came damn close."

Garfield said the railroad's directors made the decision to file for reorganization yesterday morning after losing an expected $3.7 million loan from a Swiss bank that would have kept Auto-Train out of bankruptcy court.

Auto-Train notified the Swiss bank over the weekend that is was canceling the loan after learning "that we had been deceived and misled, and so was the bank," Garfield added.

He declined to name the people he accused of deceiving the company but said Auto-Train has asked the Justice Department to investigate possible criminal actions in negotiations with middlemen who helped Auto-Train obtain the loan and an insurance policy to protect the bank in the event Auto-Train could not repay the money.

Garfield said Securities and Exchange Commission lawyers warned the company last Saturday of potential problems with the insurance coverage on the loan.

In a statement issued yesterday morning -- before the Chapter 11 filing -- Auto-Train said it "appeared that the bonding arrangement, which was an integral part of the loan, may not have been bona fide."

The loan and the insurance policy were obtained through a London firm called British Bancorporation Ltd. When the loan was announced two weeks ago, British Bancorporation was identified as a London bank.

Inquiries yesterday to the British embassy here and the international loan departments of two major local banks failed to produce any information about British Bancorporation. The business is not listed in the usual references on British banks, and embassy officials said they were not familiar with the name.

Telephone calls to a Beverly Hills, Calif., listing for British Bancorporation were taken by an answering service and not returned yesterday.

Garfield said Auto-Train officials, who have been trying for two years to raise new capital, were introduced to British Bancorporation representatives "a short time ago."

He said the company stopped pursuing some other sources of funds and concentrated on the British connection for a loan from the Banque Keyser Ullmann en Suisse in Geneva. "We were told very confidently that everything was in order," said Garfield, who had expected to begin drawing down the line of credit this week.

Under the loan agreement, Auto-Train was to pay British Bancorporation 2 percent of the loan as a finder's fee and also was to give the firm the right to buy enough stock to make it the largest stockholder in Auto-Train.

Announcement of the loan two weeks ago appeared to come in the nick of time for Auto-Train. Continental Illinois National Bank, which owns the railroad's locomotives, had sued to repossess the engines, complaining that Auto-Train was behind on lease payments. The Internal Revenue Service had slapped the company with a lien for taxes withheld from employes' checks but not passed on to the government. The Interstate Commerce Commission also has gone to court to make the railroad repay overdue refunds to passengers who had canceled reservations.

Then last week, with the new money expected any day, other creditors began clammoring for their money. The IRS hit Auto-Train with another lien for $500,000, claiming the railroad owed the government more than $2 million in taxes.

Last week the Seaboard Coast Line railroad, which provides the rails for most of Auto-Train's trips to Florida, announced it was cutting off credit and would let Auto-Train run only if it paid the daily fee of $19,000 in advance. The Richmond Fredericksburg & Potomac Railroad, which owns the tracks between Auto-Train's terminal and Richmond, said it wanted its $4,400 a day in advance, also.

Garfield came up with the cash on Friday and vowed he would continue to keep the trains running.