Regular riders on the Regional Rail's West Trenton Line know all has not been well on the 42-mile long route.

Since April, the line has experienced major delays four times, most recently Tuesday morning, when trains were delayed up to an hour.

The problem lies with wires, said Jeff Knueppel, SEPTA's general manager. About 18 years ago the West Trenton Line was experiencing major delays due to the age of the catenary, another name for the lines above trains that provide the train's electric power. Trains were speed restricted to 50 mph at the time and a fix had to be made, he said. So SEPTA replaced the lines with new ones.

The tracks that were once part of the Reading Railroad used a three-wire configuration, with a copper trolley line, an auxiliary line, and above both of those, a messenger line. SEPTA replaced the old wires with new ones but kept the same system.

Turns out, that arrangement doesn't age well, and about 10 years ago SEPTA switched to a more simple, and sturdy, two-wire catenary on most of its lines.

Along with the arrangement of the wires being obsolete, they are also hung in wide spans.

"It has the longest spans, highest speeds other than the Airport line, leading to the most vibrations and movement," Knueppel said.

The result? Cracked wires, and an unusable track. This has happened once in April, once in May, and twice this month, Knueppel said. It hasn't been a major problem until this year, he said, but it's clear now that the three-wire system has to go.

"We want the reliability," Knueppel said. "We don't want these kind of situations happening, especially when the warm weather comes."

The good news is SEPTA began this week an upgrade to the catenary along the West Trenton Line.

The bad news is that it'll take a year and a half to finish.

The West Trenton Line has two parallel tracks, and whenever a wire cracks all train traffic has to be diverted to one line for a portion of the route. The crack Tuesday damaged a train's pantograph, the rod that connects the train to its power source, so for 14 miles trains traveling the route in both directions were using one track. Even after the damage train was removed, trains were restricted to one track for five miles while the catenary was repaired.

On all of SEPTA's Regional Railroad, about 120 miles use a two-wire system, and 60 miles use a three wire configuration, Knueppel said. Most of the three-wire catenary doesn't have the wide spans seen on the West Trenton Line, though, he said. Eventually SEPTA may rid itself of the three-wire catenary entirely, but for the time being the busy West Trenton Line is the priority.

Knueppel emphasized that when the rewiring project began in 1999 SEPTA was desperate to get its West Trenton Line trains running on time, and used the three-wire configuration because it could be done quickly.

"In 1999 we had no time," Knueppel said. "That was a plan that was put together so quickly because the reliability had really, really hit bottom. If we had learned what we would find out later, we would definitely have put the two wire system in there."