The transporter fire that damaged the cars that Team Penske planned to race this weekend at Infineon Raceway has added another challenge for Helio Castroneves in his effort to catch IndyCar Series leader Scott Dixon.

The primary Dallara-Hondas for both Castroneves and teammate Ryan Briscoe were badly damaged in the fire Wednesday on Interstate 80, west of Cheyenne, Wyo. That leaves a pair of backup cars for the two Penske drivers when practice and qualifying get under way Friday on the Sonoma, Calif., road course.

Castroneves, who trails Dixon by 78 points with only three races remaining, took the loss of his best car philosophically.

“If there’s a team that can rebound from something like this, it’s Team Penske,” Castroneves said on Thursday. “They’ve done it before, and we’re going to do it again. It’s tough because you have some small bits, seats for example — I loved the seat that I had and I’m going to have to use the spare one. Little details.

Tim Cindric, president of Penske Performance Inc., said it is hard to estimate the cost of the damage from the fire that apparently started from a wheel bearing failure.

“It really comes down to the amount of work that has to be done,” he said. “The difficult part is the amount of time and effort that goes into the customization of the race cars and the trailer and the pit equipment and that type of thing.

“From a financial perspective it’s never easy and never fun, but you run a similar risk every weekend when you crash a race car.”

Cindric estimated the cost of replacing the transporter, cars, equipment and uniforms lost in the fire at between $1 million and $3 million.

The team was able to salvage some of the contents of the transporters and get it to Sonoma on Thursday.

“What we brought here today are very small things, very unique tools, things you can’t buy,” Cindric said.

He added that the Penske drivers should not be at a disadvantage at Sonoma, despite the loss.

“I’m confident that with the quality of our people, anytime we bring a backup car to the racetrack, that backup car should be prepared as if it’s going to become a race car,” Cindric said. “Otherwise, we shouldn’t really have it here at the level we participate at.”