This problem can be assume that the two railroad cars are moving toward each other, and not in opposite direction, because of the condition of an head collision.
Given: Mass of Car₁ = 6,500 Kg; Mass of Car₂ = 6,500 Kg
Velocity of each Car V = 80 Km/h or 22.22 m/s
Required: Thermal energy or Total Kinetic energy
Formula: K.E = 1/2 MV²
Solution: Total Kinetic energy or Tke = (1/2 MV²)car₁ + (1/2 MV²)car₂
Tke = 1/2 (6,500 Kg)(22.22 m/s)² + 1/2 (6,500 Kg)(22.22 m/s)²
Total Thermal energy or Tke = 3,209 Joules