Which of the following issues was the worst problem caused by early surface rail systems? a. they were too expensive for most people. b. they created the first major pollution problems in cities. c. they created gridlock with other traffic on crowded city streets. d. they were incompatible with rail systems between cities.

The answer is: C. They created gridlock with other traffic on crowded city streets.

Prior to the creation of the rail systems, the road on top of it is still used by pedestrians or other vehicles to pas through.

Because of this, the development of rail systems created gridlock with existing traffic, and all those vehicles/pedestrians were forced to find other paths to reach their destination.