Under a barrage of congressional testimony, plus protests from the rail road industry and some shippers the Interstate Commerce Commission has retreated from an earlier "get-tough" stand against railroads the agency said were ignoring orders to move out critically needed freight cars.

By a 4-3 vote on Monday, the ICC backed off from its continuing efforts to get railroads to return all freight cars to the rails within 24 hours after they stop at loading points. The commission voted instead to impose a 60 hour limit.

The vote removed possible criminal sanctions that had been pending against officers of Consolidated Rail Corp. Southern Pacific Railroad and the Santa Fe. The three railroads also had been fined $7.1 million for holding up the freight cars and ignoring an ICC service order.

The fines will be negotiated by officials of the ICC and the three railroads.

"Frankly," said spokesman Dick Briggs of the Association of American Railroads, "the order stunk." AAR spokesmen led the strong lobby effort in Congress to force the hands of ICC Chairman Dan O'Neal on the issue.

Many of the railroads complained, for example, that the ICC was jeopardizing one of their most profitable and needed lines of business - unit trains - in orders to meet the ICC 24 hour rule, which also had a 24-hour extra grace period built in.

Unit trains are trains that travel long distances intact. A railroad might, for example, stop every train entering one of its switching yards and remove each car destined for one area across the country. Then, after there are enough cars going to that one area the entire train takes off for a fast and efficient run with no more switching stops needed.

Rail spokesmen argued that the ICC service order would have forced them to move a waiting car to another switching yard, but no closer to the destination. It would become more difficult to put together unit trains.

But, according to ICC official Bob Turkington, the nationwide rail freight car shortage had escalated to a point last April when the daily average shortage was 66,000 cars. That meant that shippers were placing orders requiring 66,000 rail cars more than were available.

"There was a particularly heavy demand for grain cars and covered hoppers," he said. "And the main thrust of our order was to improve rail car utilization.

But after the Southern Pacific asked to be exempted from the 24-hour rule because it was "unreasonable," the ICC decided to hear oral arguments on the order.

"The Southern Pacific testified that there were some turnarounds they could not do under 50 hours," said ICC commissioner Robert Gresham, who proposed the new 60-hour rule. "And we have seen evidence that the shortage of cars is down drastically from its worst point."

Gresham had the votes of commissioners Rupert Murphy, George Stafford and Charles Clapp, which were enough to defeat Chairman O'Neal, who favored a 48-hour turnaround, and commissioners Virginia Mac Brown and Betty Jo Christian.

And yesterday, the first fruits of the railroads' victory were tasted by and the Seaboard Coast Line. Both were given slaps on the wrist by the commission and told that they would soon be ordered to comply with the weakened rail orders.

The two large Southeast roads would have been subjected to huge fines under the old order but plans for the fines were scrapped by the ICC when resistance to the existing rail order surfaced.