Rail freight traffic in the third quarter slightly accelerated the trend of modest improvement over last year, but analysts are far from certain that carriers can match record traffic levels posted in the last three months of 1994.

JOCPEth cost control efforts continuing and traffic running 4.1 percent ahead of last year in September and 3 percent ahead in the third quarter, analysts predict a solid earnings performance from the major carriers, with the exception of Southern Pacific Lines.Individual carriers begin reporting their earnings today, when Illinois Central Railroad meets with industry analysts. Other major carriers will report their third-quarter results over the next two weeks.

Analysts are less certain about traffic comparisons, which have to stack up against a fourth quarter of 1994 that saw 7.3 percent carload freight growth over 1993 levels and a 15 percent increase in intermodal shipments.

"Comparisons to last year are very tough," said Brian Routledge, an analyst for Prudential Securities. "Our internal economic view is that the recovery from the slowdown is probably going to be fairly modest."

"From a revenue standpoint, the railroads will continue to see grain bailing them out from results in the more cyclical traffic areas," Mr. Routledge said.

Scott Flower, a Paine Webber analyst, agreed, saying the economy may be improving less than expected.

"The peak out of the trough is not going to be much above the trough. In other words, we're going from the bottom of the gutter to the top of the gutter," he said.

"The third quarter ended on a slightly more positive note than the second quarter, but when you get beneath the numbers it was substantially similar sluggish traffic," Mr. Flower said.

Southern Pacific posted the largest volume growth at 9 percent, but analysts said results would be hurt by difficulties with maintaining cost controls.

Other volume leaders were Burlington Northern and Union Pacific, both up 6 percent last month. Conrail showed the largest decline at 3 percent.

Among carload commodities, grain continued to be the strongest group with a 21 percent year-to-year increase. Coal volume picked up 4 percent as utilities began to rebuild stockpiles affected by late summer heat waves. Chemicals traffic rose 3 percent.

Automotive shipments were 8 percent higher during a four-week Teamsters strike against Ryder Automotive Operations Inc., the nation's largest car hauler. Based on industry averages, the railroads handled approximately 100,000 more motor vehicles in multi-level cars last month than the prior year.

While carload freight volumes improved overall, intermodal continued to slide downhill with little sign of a significant upturn on the horizon.

Shipments handled were 2.1 percent lower in September and 2.6 percent lower in the second quarter.

"The pressure will be on intermodal through the fourth quarter and probably into mid-1995," said Doug Rockel, a Furman Selz analyst. "We see little evidence that will change. Truckers have been unusually aggressive in pulling TOFC (trailer on flatcar) service off the railways."

"It never ceases to amaze me how trucking companies can run freight at prices that from an economic standpoint cannot be making these guys any money," Mr. Routledge said.

"Western carriers are seeing much more buoyant traffic," Mr. Flower said. ''Burlington Northern and Santa Fe are showing terrific numbers in different parts of the product mix. They have a full head of steam, despite the economy. Santa Fe's intermodal is spectacular, given the market environment. It's a reflection of the real strength of the service product and the business strategy."

Santa Fe's intermodal volume was up 11 percent in September and 8 percent in the quarter. The other carriers' combined volumes were down 5 percent during the third quarter and 6 percent in September.