Auto-Train Corp. has received permission from the Interstate Commerce Commission to offer joint service with airlines.

Under the plan, travelers will be able to put their car on Auto-Train, then fly to Florida and pick it up.

Auto-Train has already signed agreements with Eastern Airlines to offer the joint service, which will probably start in mid-January.

The fly-and-bring-your-car arrangement is expected to be a boon to Auto-Train, which has been struggling to make a profit. The company has lost $677,000 in the last 15 months and is expected to report another loos when results for the quarter ended Nov. 1 are released next week.

"It will have a very positive impact on us, bringing a new dimension to our services," said Richard Goldstein, vice president and chief operating officer.

Goldstein said the train frequently fills up with passengers, but has capacity for additional cars. Carrying cars is more profitable than carrying people, company officials say.

Auto-Train had been seeking approval of the joint service for months. The ICC gave preliminary approval in October, but that decision was appealed, forcing the company to cancel the original starting date.

Objections were made by rival firms that deliver cars to Florida, either by driving them or hauling them on trucks.

Goldstein said Auto-Train still must obtain ICC approval of its rates for carrying cars. He said the charge will be approximately the same as the $99 now charged for cars whose drivers ride on the train.

The tariff with the fares will be filed with the ICC next week, he said, and normally would be effective in 30 days, allowing the service to start in mid-January.

December is usually Auto-Train's busiest month for southbound travel, as winter-residents of Florida and holiday vacationers head south. The train runs once a day from Lorton, Va., to Sanford, near Orlando.

The joint service with Eastern Airlines will be a package deal including air travel, auto-shipping charges, ground transfers between the airport and rail terminal and overnight accomodations while flyers wait for the car to make the 14-hour trip.

The ICC authorization does not restric the service to Eastern Airlines, but does require simultaneous travel by the driver. Customers will be able to drop their cars off or pick them up 48 hours before or after their flight, Goldstein said.

He would not estimate how many flying customers Auto-Train will attract but he said Eastern is promised space for 30 cars, 20 days in advance of the travel date and that guarantee decreases as the departure date approaches.

Goldstein said the service would expand Autostein said the service would expand Auto-Train's market, attracting some customers who insist of flying and others who won't take the train unless they can get one of the limited number of bedrooms.

Eastern will handle reservations for the joint service, which will be offered through travel agents. Auto-Train's regular service is not sold by the travel agents so the company can avoid paying commissions.

To make the plane-train service competitive, Auto-Train this fall adjusted its fares, cutting the car portion from $159 to $99 and raising the passenger fee.