Metro's oldest railcars are becoming so worn down, their aluminum floors are starting to crack.

So far, the floors near the doors on 21 rail cars have cracked after running for 32 years. Metro has 290 of the oldest 1,000-series cars. They are deployed throughout the system.

Metro officials say there is no immediate danger for riders. When cracks appear, the cars are pulled out of service and the floors are welded back together.

Metro's railcar chief Dave Kubicek tells The (Washington) Examiner they may start installing steel reinforcements under the floors to prevent the problem.

The transit system needs all of its railcars to keep up with record ridership. The oldest rail cars are not due to be replaced until a new 7,000-series car comes into service in about five years.