For years, Amtrak blamed chronic delays for some passenger trains such as average 40-minute waits between Salt Lake City and Elko, Nev. on bad dispatching by freight lines that own the rails.
Freight carriers, in turn, pointed to insufficient capacity on shared rails.
The U.S. Transportation Department's inspector general issued a report this week that sides mostly with Amtrak and points at freight railroads as the biggest delay culprit.
The report said the two top causes for such delays outside the Northeast where Amtrak owns and controls most of its own rails are "host effects," or dispatching by host railroads that does not give Amtrak required priority, and "slow orders," or speed restrictions because of repair work or poor conditions.
It is important to know what causes delays because Congress in recent years authorized $12 billion to build infrastructure to improve capacity and help speed up intercity rail service. But the report said host effects and slow orders "may not require capital investment to address."
The inspector general analyzed travel data from 2002 to 2007 to see why Amtrak trains outside the Northeast run into long delays, making service undependable, scaring away customers and cutting into Amtrak's earnings.
The study noted that Amtrak's on-time performance in the Northeast ranges from 75 percent to 90 percent. On long-distance lines elsewhere, on-time performance falls below 55 percent.
Some individual stretches consistently experienced especially long delays.
For example, the study said the California Zephyr which travels from Chicago to San Francisco Â averaged 40 minutes of delay between Salt Lake City and Elko. The study found about half the waits came from "slow orders." It pegged about 8 percent of delays on capacity problems. About a fourth occurred when the train arrived more than two hours late to the stretch, creating scheduling problems with other trains.
The study said Union Pacific's "host effects" also led to long delays on rails it owns including that Salt Lake City-to-Elko segment and are longer than on lines controlled by other freight railroads. It said such delays on Union Pacific rails "average 38 minutes, 30 seconds of delay over an entire long-distance route."
Union Pacific spokesman Tom Lange said that although the railroad encountered "challenges related to Amtrak on-time performance during the time period of this study," since then "our current levels of service are significantly improved and deliver high levels of reliability."
For example, he said, "Union Pacific continues to operate the top-performing passenger service in the United States on the Capitol Corridor between San Jose and Sacramento, with up to 32 trains per day. As Amtrak measures performance, these trains routinely achieve 97 percent or better on-time performance, which is better than Amtrak's Northeast corridor."
The inspector general noted that for years,"Amtrak points to freight railroads' dispatching practices as the cause with the greatest impact on Amtrak train delays, while the freight railroads contend that capacity limitations, or insufficient infrastructure for rail traffic levels, contribute more heavily."
It added, "Freight railroads' dispatchers are required by law to give Amtrak trains preference when freight trains and passenger trains operate on the same routes. However, Amtrak and the freight railroads disagree over whether preference is actually always given to Amtrak."