Old rail cars provide North Carolina DOT a new way to install temporary road bridges

By Jeff Stagl, Managing Editor 

After Hurricane Helene slammed through North Carolina on Sept. 27, 2024, with torrential rains, strong winds and tornadoes, the road infrastructure damage left behind was beyond extensive. Thousands of miles of highways and hundreds of road bridges were critically damaged or destroyed. 

In December, North Carolina officials estimated the total cost of damage in the state at nearly $60 billion, including $44.4 billion in direct damage costs. 

To address the missing or severely battered bridges as quickly as possible, North Carolina Department of Transportation (NCDOT) officials are aiming to install temporary bridges at a number of locations. And some of those temporary structures feature a somewhat surprising deck: a rail car. 

The NCDOT is using flat cars that have been removed from service as the basis for 40 temporary road bridges. So far, 37 have been completed, with the last three to be finished by the end of February. 

The bridges are considered a temporary solution until permanent structures can be constructed, said NCDOT Division 13 Assistant Construction Engineer Jody Lawrence in an email. 

The flat cars are sourced from railroads all over the country, including CSX and Norfolk Southern Railway, he said. The main steel structure of the rail cars — minus the trucks and wheels — is used as the deck of the bridge, then asphalt is paved over it. 

The final stage of completing a temporary bridge is paving over the old rail-car structure with asphalt. The bridges are a fast-to-install and economical option, NCDOT officials say. North Carolina Department of Transportation

One main advantage is how fast a temporary bridge can be completed with old rail cars. 

“A single span can be installed, in some cases, in as quick as 24 hours. But in most cases, it has taken 48 hours,” said Lawrence. “The multi-span bridges that require a more complicated substructure can take two weeks to a month to complete.” 

Moreover, the bridges require minimal maintenance while the construction method is economical. On average, temporary bridges with rail cars cost half as much as structures built with other materials, said Lawrence. 

“But this is dependent on the location, whether it’s a single-span or multi-span bridge, and the substructure type,” he said. 

The idea of using rail cars for temporary road bridges was hatched shortly before the hurricane reached North Carolina. Innovative Bridge Co. LLC (IBC) reached out to NCDOT Division Bridge Maintenance Engineer Justin Rice with information about the bridges just before the storm hit, said Lawrence. 

“[We] looked at the data provided and discussed it with our structures management unit. [We] then decided to proceed with installing these as temporary structures to provide connectivity back to our communities while more permanent repairs were being developed,” he said. 

The NCDOT contracted IBC — which is based in Burke County, North Carolina — to repurpose the old rail cars as temporary bridges. 

At first, NCDOT officials weren’t aware of any other states that had used old rail cars as decks for temporary road bridges. But they since have learned that several other states have done so, including Indiana, Iowa, Louisiana and Mississippi, said Lawrence. 

The NCDOT plans to keep the rail-car decks in inventory after they're used and redeploy them for future emergencies. North Carolina Department of Transportation

“Tennessee also started using them after Hurricane Helene for temporary structures after they saw our success with them,” he said. 

Although the bridges are designed as temporary structures, some can last a long time under normal traffic conditions. 

“This is new to the NCDOT and we have no data for this, but some of the other states that have utilized them have had some of them in place for 20-plus years, is my understanding,” said Lawrence. 

For the NCDOT, longevity isn’t the main goal. Instead, the unique bridges provide the state with something that figures to pay off for a long time. 

“Once we are done with these bridges, the plan is to keep them in inventory and spread them across the state so that they can be utilized elsewhere for future emergency use,” said Lawrence.