Wide discrepancies in the levels of technology and service among the subway system’s 22 lines are the result of poor management and an “unfair distribution of resources,” a riders’ advocacy group said in a survey released yesterday.

In its annual survey of the best and worst subway lines, the New York Public Interest Research Group’s Straphangers Campaign said it was no surprise that service on lines with newer cars was better, but it was unfair that a majority of the system’s riders received no benefit from improved technology, because the newer trains have been allocated exclusively to the L and the nos. 2, 3, 4, 5, and 6 lines.

“We don’t know if it’s intentional or not, but they are related,” the Straphangers Campaign coordinator, Neysa Pranger, said. “If they were better managed, they would distribute their resources more fairly.”

Straphangers does not accuse New York City Transit of discriminating against riders on the basis of geography or affluence, however. The 4 and 5 lines, for example, which traverse the wealthy Upper East Side of Manhattan, also pass through neighborhoods in the Bronx and Brooklyn. Moreover, their new cars replaced the system’s oldest, the “redbirds.”

The survey, which is based largely on data collected by the Metropolitan Transportation Authority, ranks the trains by six measurements, and two of those are affected by the age of a train: a car’s breakdown rate and the audibility of in-car announcements.

For the second consecutive year, the survey of the subway system ranks the no. 6 line, which has been running the fleet’s newest R142 subway cars since 2000, as the best overall. The line remains one of the most crowded, however, ranking 15th in that category.

The quality of service is significantly worse on lines with older subway cars, according to the survey. With the exception of the J, Z, and Q lines, lines with older subway cars, including all of the lettered lines except the L, ranked at the bottom of the list.

Cars on the lettered lines are expected to be replaced beginning in October 2006 with the next generation of high-tech cars, which include automated announcements and digital displays similar to the R142s.

A spokesman for New York City Transit, Charles Seaton, said that the oldest cars are replaced first and that, with a fleet of more than 6,400 cars, not all lines can be given new cars simultaneously.

Other rankings in the survey unrelated to a car’s age include amount of scheduled service, regularity of service, interior cleanliness, and chance of getting a seat.

The N line was ranked the worst line in the system, according to the annual survey. It ranked last for in-car announcements, meaning most of the announcements were inaudible, and tied the L as the line with the dirtiest car interiors. The no. 1, the now defunct no. 9, and the W were ranked the cleanest lines.

Lines with newer cars were also among the most crowded, topped by the L line. Riders on the V, R, and Q lines have the greatest chance of finding a seat, the survey found.

The G line has long been referred to as the “ghost line” for infrequent service. The M ranked last for scheduled service while the G ranked 17th, five slots better, but the G was rated most likely to break down.

The breakdown rates for the system overall have also improved, from one every 50,000 miles in 1994, to one every 140,000 miles in 2003, to one every 157,000 miles today. But those improvements underscore the difference between older and newer cars. Before breaking down, the system’s newest cars travel an average of 200,000 miles more than the oldest cars. How far a car travels in, say, a month depends on the length of the line and the frequency of scheduled service.

The associate director of the MTA’s Permanent Citizens Advisory Committee, William Henderson, said that most lines, despite differences in car technology, provides similar service overall.

Nonetheless, for those who ride inside older cars, ill will toward the MTA is understandable, he acknowledged.

“I’m sure if you rode on a car with a roof patched with duct tape, you’d feel it was unfair,” Mr. Henderson said. “But I don’t think it’s intentional of Transit.”

Despite the quantifiable improvements, and the billions of dollars invested in the system since the first MTA capital plan was introduced in 1982, ill feeling toward the subway authority persists. Last week, Newsday reported that subway riders in a survey conducted by the MTA ranked the system a 6.1 on a scale of 10 – the same score riders gave the system 10 years ago. Since 2000 alone, New York City Transit has spent $2.75 billion to upgrade and replace 1,800 subway cars.

This was the eighth survey released by the Straphangers Campaign since 1996, which did not conduct a survey in 2001 after the September 11 terrorist attacks.