Inside SEPTA’s hospital for sick train cars

Just past the 69th Street Transportation Center in Upper Darby, amid an array of railroad side tracks, sits a hospital for sick subway cars.

There, mechanics, welders and machinists brace cracks in the frames of Market-Frankford Line trains between two plates of steel, a process the workers compare to making a hoagie — all in a race to keep SEPTA’s most heavily traveled line running.

“It’s a challenge with a fleet that’s had systemic issues basically since we got it,” said Ed Carruthers, assistant chief of rail equipment maintenance. “We get backed up.”

SEPTA needs about 96 functioning cars to provide the El’s current level of weekday service, officials said. On average, about 85 cars are available, with a steady stream of them rotating off the line for inspections, structural repairs, general overhaul, or else receiving routine maintenance in what Carruthers calls the “minute clinic.”

As a result, the intervals between Market-Frankford trains can lengthen, from the usual six minutes to nine or even 12 minutes, said Scott Sauer, SEPTA’s chief operating officer. Passengers waiting on platforms fume as the SEPTA app and station announcements report service delays.

“They hear that so many times that it becomes noise,” Sauer said. SEPTA’s chief operating officer. “They’ve grown weary. … I’m sure the next thought in their minds is, well, what are we doing about it? We want our customers to know that we’re battling every day.”

Crews regularly repair or replace worn-out components on the M4 cars, the oldest of which have been running on the El for 24 years. Rail cars typically last without major structural issues for 30 years or more. Broad Street Line cars, built in 1984, have fewer maintenance issues than the El cars, SEPTA says.

The work never seems to end. As soon as the Upper Darby shop complex makes progress on cracks, rust damage and worn parts, “something else gets pulled out of service,” Carruthers said.

The M4s had issues when they arrived in Philadelphia in the late 1990s. First, the car bodies failed a stress test because they weren’t rigid enough to withstand the twisting and bouncing of a train in motion. The cars were reinforced with more steel, but then they were too heavy for the elevated line, and the manufacturer had to slim them down.

In 2017, SEPTA mechanics pulling up the floorboards during an overhaul of several M4s found cracks in the body bolsters, 94-inch steel beams that span the car on either end, supporting the weight of its frame and connecting it to the wheel assemblies, which pivot as the train moves.

The flaws started with the welding that attaches air ducts used to cool the train’s traction motors to the bolster beams, SEPTA says.

Soon, inspections found at least 40 cars with cracks. The transit agency started a structural repair program for the fleet that has cost $19.3 million over the last six years, including construction of a special building with a machine shop, enough height for cranes, and work bays with pits for undercarriage work.

Now, the authority is accepting bids on a contract of as much as $850 million to build about 200 new rail cars for the Market-Frankford El. SEPTA says it has set aside money for the purchase. But the last of the cars could arrive as late as 2030, meaning the shop must keep the current fleet running during the transition.

“Even when we have a minor defect that needs attention, it sometimes takes awhile to turn that car over to get it back into service,” Sauer said. He praised the “innovative and creative” work of the employees for holding the cars together.

It can be hard to hear in the shop, amid the whine of diamond-bit drills grinding into steel, mallets banging, generators humming, and the loud whoosh of welding torches as they shower white-hot sparks onto the floor.

“A lot of technology on these cars isn’t supported anymore,” Carruthers said. That means scrounging for parts from a small number of independent specialty factories or figuring out how to build them from scratch.

The parts are not simple. “There are long lead times: Just the gear unit has 50 separate parts,” said John Macawen, SEPTA’s director of vehicle engineering. “A whole truck overhaul requires replacing as many as 1,000 parts,” he said, using the railroad term for the wheel assemblies.

Adtranz, the original manufacturer, built the M4s for $285 million and delivered them to SEPTA from 1997 through 1999. That company no longer exists; it was absorbed into Bombardier Inc., and the French multinational Alstom acquired Bombardier’s rail business in 2021.

One problem the mechanics face now concerns the doors to the subway-elevated passenger cars. Aging rubber weatherproofing strips are getting brittle, and sometimes the doors don’t close tightly. Replacement seals are installed in the shop.

On top of that, the motors that open and close the El doors are failing, and the computer units that control them are wearing down. Nobody makes the computer hardware anymore. Outside engineers are designing a new version. And SEPTA will have to find someone to write modern code for the software.

El trains suffer a mechanical breakdown en route that requires them to be towed to the shop an average of 10 times a month, according to SEPTA figures.

The harder struggle is mustering enough cars to be able to offer robust service, officials said. The availability of cars fluctuates as they are rotated off the line for scheduled structural repairs, maintenance and inspections, as well as emergency breakdowns.

About 85,000 passengers a day ride the Market-Frankford Line, a little more than half the pre-pandemic level, but the El remains by far the most used in the system. It also connects riders to 60 bus lines.

SEPTA has little flexibility.

For one thing, M4 cars operate in married pairs, “joined together forever and ever until death do they part,” Sauer said. When one car develops an issue, two cars are offline while the first gets repaired.

Second, SEPTA rail cars are not interchangeable.

MFL cars, for instance, run on a unique track known as “Philadelphia Trolley Gauge,” which is about six inches wider than the standard size, Sauer said. But they have a third-rail electrical power system instead of using overhead wires, so spare trolleys can’t be used as substitutes.

SEPTA was organized in the early 1960s from the disparate systems of defunct railroads.

“We’re kind of a conglomeration — none of our rail cars can run on another rail line,” Sauer said. “We can’t intermingle. We buy a fleet that’s dedicated to a particular service.”

And so the teams at the Upper Darby shops will keep improvising until the M5s arrive.