What is the magnitude of the force must each engine exert

Question

A freight train consists of two 8.3 A????1 10⁴ kg engines and 45 cars with average masses of 5.95 x 10⁴kg each.

m = 8.3 x 10⁴ kg
m₂ = 5.95 x 10⁴ kg
f = 7.6 x 10⁵ N

1) What is the magnitude of the force must each engine exert backward on the track to accelerate the train at a rate of 5.00 x 10^-12 m/s² if the force of friction is 7.6 x 10⁵ N, assuming the engines exert identical forces? This is not a large frictional force for such a massive system. Rolling friction for trains is small, and consequently trains are very energy-efficient transportation systems.

2) What is the force in the coupling between the 37^th and 38^th cars (this is the force each exerts on the other), assuming all cars have the same mass and that friction is evenly distributed among all of the cars and engines?